Friends and family tell PEOPLE the show's youngest winner was drinking up to three bottles of vodka a day

The video is horrifying: Survivor: China winner Todd Herzog, unable to walk, slurs his words as he admits to drinking an entire bottle of vodka. The footage, which will air on Dr. Phil on Monday in a show about Herzog’s difficult battle with alcoholism, shocked Survivor fans across the web.

Several of Herzog’s closest friends and relatives talked to PEOPLE about his struggle – not for publicity, they say, but to raise awareness of the complicated issue of alcoholism. “We have received so many messages from people who are battling the same issues as he is,” says his mother, Shirley Herzog Keeler. “And Todd said that if his story can help one person get the help they need, he’s ready to go public with it.”

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“I have been very protective of him,” says his close friend Courtney Yates, who placed second to him on Survivor in 2007. “But for better or worse, this is public now. He’s accountable to everyone. I think it’s important for Todd to know how much people want to see him get better. I hope he can inspire other people who are struggling.”

A Growing Problem

Those closest to Herzog explain that his alcoholism didn’t happen suddenly. He had his first drink at age 22. At first, he had it under control, but his drinking and behavior soon grew more erratic.

Yates saw the problem firsthand in January when she and Herzog went on a seven-day Caribbean cruise. “It was a typical cruise,” she says. “We swam with dolphins. There were piña coladas everywhere. But Todd’s behavior was more extreme than that. There was the shaking and trouble sleeping. It was past the point of just having fun. I told him, ‘Todd, you need to get this together or you’ll be #86 on VH1’s list of reality stars gone bad.’ Obviously that was a joke, but it started a serious conversation.”

When he returned home after the cruise, he checked into rehab. “For a while, it was working and he was staying sober,” says Yates. “But then he moved from Florida to Utah. I think he felt isolated, and he relapsed.”

Hitting Rock Bottom

Things grew more serious. Herzog would drink up to three bottles of vodka a day, according to his mom, Keeler. “In the family, we would take turns on who’s going to check on him, because we didn’t know if he was going to die overnight,” she says. “I watched him deteriorate. When he wouldn’t answer the phone, I’d panic, thinking we had lost him.”

Herzog was hospitalized at least twice for alcohol poisoning, according to Keeler. “He said to me, ‘Mom, I don’t know why I do it,’ ” she says. “I felt like I was losing him.”

“When I heard about his problem, he called me and I said, ‘Todd, come to my house for a few weeks. We’ll figure out what to do,” says Survivor: Pearl Islands and Heroes vs. Villains winner Sandra Diaz Twine, who is also a close friend. “I would do anything to help him.”

Desperate, Herzog’s mother contacted producers at Dr. Phil – a decision not everyone in Herzog’s circle agreed with. “When you’re at the end of your rope, you’ll do anything to save the life of your child,” Keeler says. “Todd wasn’t happy at first, but I figured that I would rather him be alive and mad at me than to be dead.”

When Herzog and his family taped the Dr. Phil show earlier this month, there was a familiar face in the audience: Sandra Diaz-Twine flew out to be there for her friend. “It was tough,” she says. “He threw up on stage. … But I told him, ‘Todd, stay with this. You can do it.'”

After the taping, the show sent Herzog to a 90-day rehab in Texas.

Well Wishes

Herzog had always been popular in the Survivor family. In one of his last Survivor-related appearances before going to rehab, he attended Hearts of Reality, a gathering of reality stars who raise money and awareness for the charity Give Kids the World. Mingling with more than 100 other reality stars, Herzog’s dedication to the cause stood out.

“He would interact with the children, make people feel welcome,” says organizer Mike Nunez. “He is one of our best. He wants to use his notoriety to help inspire others. That’s why it’s hard to see him going through this.”

As news of his battle spread, Herzog’s mother received “thousands” of emails and messages. “Every single one of them was positive and encouraging,” she says.

Adds Yates: “People have been nothing but kind and supportive of Todd. Former Survivors, fans, people from the show. He has heard from people all over the world. It speaks well of him that there are so many people who are sending their thoughts and prayers.

Those close to Herzog vow to help him. “Todd needs to know that he’s not going to lose one friend from this,” says Diaz-Twine. “There are people rooting for him. He has always persevered in the past, and we know he can do it now.”

Although he has limited access to phone and Internet in rehab, he is occasionally allowed to read some of the well-wishes, his mother tells PEOPLE.

On Monday, he posted a private message on his Facebook page. “To all of those sending support and love to me, thank you,” he wrote. “I am currently in treatment and doing fantastic and look forward to a healthy and sober life when I leave.”