Image copyright Dopey podcast Image caption Chris and Dave (right) founded the Dopey podcast anonymously

When two former heroin addicts started a podcast to share wild drug stories, they had no idea what success - and tragedy - awaited them.

Dopey has been described as the podcast you would not want to bring home to your parents.

And yet here is the host, ready to record it in his father's 21st-floor apartment in Chelsea, New York. The weekly show has been recorded on this kitchen table multiple times since it launched in 2016.

Dave - the son, now in his mid-40s - has nothing to hide. He shares no-holds-barred stories of his past as a heroin addict with anyone who tunes in. His father, a science teacher called Alan, is an unlikely fan. He proudly counts the online podcast reviews every day. "You should check them out," he urges. "What are they called? iPad reviews? iPhone reviews?"

This month, Dopey passed two million downloads. About 15,000 people tune into each weekly episode. The audience first came for the laughs and wild anecdotes, but they have stuck around, forming an informal support network, across the US and beyond.

Dave started the show with his good friend Chris, whom he had met some years before in rehab.

They were both struck by the lack of accurate representations of drug-usage in the wider world. "Everything was either super schmaltzy, or laid out super thick to conjure sympathy or sadness," says Dave. He had found himself seeking out TV shows, films and books with junkie characters. "I wanted to hear about the experience I was living so I could compare notes, or understand. How did they get out of it? Why did they do it?"

So when Chris announced that he wanted some sort of creative project, Dave suggested an honest drug-themed podcast.

Neither of them was convinced anyone would listen to their ramblings. They sat on the first episode for weeks before publishing it. However, when it finally went online, they found people were coming across it after searching for "heroin podcast". Apparently a demand was out there, and word started to spread.

'The point of this podcast is to focus on the war stories' - Chris, episode one

The first-ever episode of Dopey was recorded in Dave's apartment in 2016. He and Chris had no special equipment. They just spoke into the internal microphone of an open laptop, presuming this was just going to be a one-off experiment.

Dave was four months into sobriety at this point; Chris had a year and a half. Dave's past involves 15 years of heroin addiction, while Chris, who was 10 years younger, had a childhood that saw him drinking alcohol at 11, and ending up taking heroin and cocaine intravenously.

For the show, Dave - confident and bolshie - took the lead. He interrupted and provoked his friend, deliberately, in a bid to demonstrate rapport and create chemistry. Chris came across as more unsure, worried about how his voice sounds. Yet he warmed up and somehow found a way to tell the most outlandish stories, without sounding like he was bragging.

In the first episode, Chris calmly told a tale about stealing phenobarbital from a veterinarian, after initially trying to pretend his cat was having seizures. "They told me something like … 'Please fill out some paperwork and can we see your cat?' … Obviously, I had no cat with me."

He also tells of the time he escapes rehab and the police pick him up, only to drop him across the road from the centre so he could run away again. "That's some half-assed police work," said Dave.

The dynamic worked. Before long, they developed catchphrases. Dave ended every episode saying, "Stay strong, Dopey Nation", while Chris always said "Toodles" instead of goodbye, which Dave hated. "Please stop saying toodles" was often the fade-out postscript.

Their audiences soon extended beyond the US - to the UK, Canada, Australia and New Zealand. They were also drawing in addicts' friends and families. "And then there were all the voyeurs who love to hear crazy drug stories," Dave says. "Because it is illegal, it is dangerous, it is taboo ... Drug stories are always pretty fun, for the most part, until you get to the consequences."

Letters and emails started pouring in from fans urging them to keep it up. People sent them artwork and songs. Some even got Dopey tattoos.

Image copyright Dopey podcast Image caption Various fans have got Dopey tattoos

Yet, despite the growing success, Dave started to worry that Chris was losing interest. He was studying for a PhD in psychology and had various internships on the go. It seemed he no longer had the time or enthusiasm for Dopey.

And then one day, Dave suddenly found himself alone at the microphone.

'The worst thing that could ever happened has happened. Chris relapsed and died' - Dave, episode 143

These were the words that opened the show on 28 July 2018.

It was two and half years since Dopey began. Dave was as direct as ever, but his voice was drained. At one point, it cracked slightly.

He had only just begun piecing together what happened himself. Chris had died on Tuesday and he was recording just two days later. He had not been sure whether to go ahead with an episode, or to end the show altogether, but he felt he owned the regular listeners some sort of explanation.

He told them he did not know Chris had secretly begun using again.

Chris's girlfriend, Annie, had become suspicious. She had called Dave in the early hours of Tuesday morning, asking if he would check on him. Dave sent him a message at 6.30am. Chris replied at 6.31am: "I am fine. Still alive. Not great. Will talk later."

At 10.30am, Dave got a call from Annie saying she had found him dead. He had taken a mixture of drugs, including fentanyl. He had been ordering it from the dark web. He had also ordered clean urine so he could pass drugs tests as part of his own ongoing care.

No-one is sure exactly what sparked this descent. There are two theories. Either he confiscated and consumed a client's pills at the recovery centre he worked at. Or it is possible that he was prescribed painkillers after tearing a ligament, and this set him off again.

Dave was numb when he heard the news. Just over a month beforehand, one of his best friends, Todd, had also died. Todd had been the one exception to the Dopey rule that you could not appear on the show if you were using. He was a semi-regular guest.

Media playback is unsupported on your device Media caption On America's trail of destruction

Ultimately, it was a 10-dollar bag of heroin, with a lethal amount of fentanyl, that killed Todd, according to Dave.

Fentanyl - the drug at the centre of the US opioid crisis - is a synthetic painkiller, said to be between 50 and 100 times stronger than morphine. It has flooded the drugs market, with much of it finding its way on to the internet from China.

Dave says that within a year, five major figures from the Dopey community died from fentanyl usage. They also lost an intern, Andrew; the guy who set up their Facebook page, Dave; and a listener, Troy, who one of the first people to write in.

"I used heroin for 15 years and I didn't know anyone who died," says Dave. "That's my experience. I am sure there are other people who had a ton of friends who died from heroin overdose. But fentanyl becomes available and now you have death everywhere."

'Getting honest is the biggest hurdle in getting sober' - Dave

It is almost a year since Chris died and Dave has still never missed a show. At first, he was worried listeners might not stick with it. "They loved Chris," he says. "He was so likeable. They liked him more than me."

Dave recalls getting a series of angry emails from one fan, who complained that the show had moved away from casual drugs banter. "And I was like, listen man, if two of your best friends died from an overdose…"

However, that sort of backlash was rare. Most of the audience showered Dave with support. Does he feel he has to continue with the show? Is it a responsibility?

"No," he insists. "I do the show because I love it. I love every aspect about it."

Nevertheless, it has become a much greater workload. Not only because he is now the solo lead, but also because the audience has grown so much and he wants to keep it interesting. The show has always had guests, but recently they have included bigger names, including actress Jamie Lee Curtis and former Guns N' Roses drummer Steven Adler.

As a day job, Dave has been a waiter in one of New York's most famous Jewish diners, Katz's Delicatessen, for 11 years.

At 3pm on a weekday, the place is rammed. The 131-year-old joint is renowned for its enormous pastrami sandwiches. It is also where When Harry Met Sally's famous fake-orgasm scene was shot.

Image copyright Katz's Deli Image caption Dave also worked at Katz's Deli when he was at high school

Dave is more than a waiter here. He also does the restaurant's social media and runs the outside catering. "Hey Fanny! Fanny!" he calls to a passing colleague. "How long have you known me? What you think of the show?"

"He's my Jewish son," she tells me, her Ecuadorian accent having incorporated a New Yorker's twang. "The show helped him out a lot, and I think it is very helpful for anyone out there who had similar problems ... And finally - thank God! - he has stopped [the drugs]."

Restaurant manager, Charles de La Cruz, is another long-term colleague, who remembers when Dave worked at the restaurant during a relapse. "It was a dark road, it was grim," he says. "But now he is using his experiences to help other people. I think it is amazing."

Dave insists, again and again, that he does not make Dopey to help people. He makes it because he wants to be entertaining. But the fact that it is entertaining seems to be helping people.

One of the people who says Dopey has helped them is based in London, England.

He does not want to give his real name. On Twitter he goes by the handle Secret Drug Addict (@scrtdrugaddict) and says he was heavily into drugs when working for the band Oasis in the 1990s.

"What I really love is seeing this group of lunatics all connecting via the Dopey social media platforms, and supporting, laughing and helping each other to rack up another day without using drugs," he says. "I wish when I stopped doing drugs back in 2007 there was something like this that I could have been part of."

'This Dopey Nation thing is amazing' - Dave's dad, episode 191

Back in his dad's apartment, Dave is somewhat frantically trying to get started on the latest episode.

He has a time limit. He has to get the episode up, and he and his partner, Linda, also have to relieve the babysitter. They have two children together - which is one of the reasons he tries to retain some anonymity.

He records here in Chelsea, because it is more central than the home they share together and nearer to his work. His childhood home - a public-housing development - sits between the skyscrapers, with the Empire State Building on one side and the gleaming new Hudson Yard towers on the other.

Image copyright Dopey podcast Image caption Dave, Linda and Alan recording Dopey at the kitchen table

The show's format has evolved. The concept, he says, is that if there is guest in the first half, then the second part should feel like "coming home", like when you are young and regaling stories about the night before.

Today's episode has a family focus, featuring both his dad and Linda. Alan is delightfully chipper and appears comfortable with the warts-and-all sharing. He remembers a personal lowest point: the day he had to clear out Dave's filthy apartment when he was left for rehab. Dave had scrawled the words "help me" on the walls.

"Do you remember writing that?" asks Linda. She dabbled in some drugs before becoming a counsellor, and seems largely unshockable, yet even she is taken aback. "No, that's scary," he replies, before quickly transitioning into an anecdote about his pet fish at the time. Comedy, he has said before, is always the flipside to the super-tragic stuff.

It is striking how much support Dave now has in his life. His father, his partner, his colleagues.

Dopey reaches a lot of people who don't have that. "Dopey is not a cure," he had said earlier. "Someone told me they think of it as a supplement to 12 steps [the rehab programme]. I see it more as a talk show for addicts, to keep them company and make them feel less alone."

On air, Alan says it is a "miracle" that his son cleaned up. "He is a pain in the neck, but I love him," he adds.

Then, after almost two hours of off-the-cuff chat, episode 191 is over. Dave signs off until next time. "Dopey Nation, stay strong ... And toodles for Chris, and Todd, and everyone."

For more information and support on addiction issues, visit BBC Action Line.