You can still catch a few glimpses of the old Molly Daley, from before the dementia diagnosis two years ago, when she laughs for no reason, when she hugs her son and tells him she loves him, or when she pretends to box with her youngest grandson, wearing pink gloves and a padded helmet.

That’s the Molly who enjoyed drinking a cold beer with her dinner, going on road trips, and lending a hand to her friends and neighbors.

But that Molly is now elusive, more often replaced by a vacant gaze hiding the suffering as the disease slowly takes over her brain.

Molly and Joey Daley at Christmas in 1988. Courtesy Joey Daley

"That look of confusion, where she’s trying to process what’s going on, it’s just like a blank stare and that gets worse over time," her son, Joey Daley, told NBC News. "It’s like, just a little bit, dementia has taken a little bit more of her away."

Such is the agonizing nature of what's called "Lewy body dementia," which Joey Daley began chronicling in January through a painfully honest YouTube series centered on his mom.

Molly, 66, was diagnosed in 2015, and Daley found himself yearning for more information from other caregivers like him about what to expect as the disease worsened.

When he found resources lacking, he decided to put the spotlight on Molly and their own family’s struggle — reaching the hearts of millions who have watched the videos around the world in the process.

“Before these videos, you couldn’t explain it to people,” Daley said, adding that he couldn’t watch his mother deteriorating without giving the ordeal some purpose.

Now, after the ongoing series sprouted a grassroots network of caregivers and supporters called Molly’s Movement, Daley, 46, said the videos have been the most rewarding thing he’s ever done.

"I had no idea it would touch that many people," he said.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Dementia with Lewy bodies is the second most common form of the disease in older adults after Alzheimer’s, affecting more than 1.4 million Americans. Abnormal clumps of a protein building up in brain cells cause the disease, which is characterized by a gradual loss of cognitive functions. Patients experience visual hallucinations, REM disorders that cause them to physically act out dreams, and tremors like those in Parkinson’s disease. But unlike Parkinson’s, Lewy body dementia affects wider swaths of the brain, interfering with a person’s everyday life and their ability to carry out typical activities or solve problems.

“I don’t want to stop early. I want people to understand how bad it gets.”

About three years ago, basic tasks like paying bills, driving a car or taking medication became challenges for Molly, who at the time was living alone in Columbus, Ohio. Then, after an infection landed her in the hospital, her children stepped in. She now lives closer to her family in a nursing home in nearby Dublin, where her son and daughter visit on alternate days, taking her out for shopping trips, the occasional pedicure or haircut, and family dinners.

Daley sits with his mother at his home in Dublin, Ohio. Maddie McGarvey / for NBC News

Daley never knows what state of mind his mom will be in on each visit. Sometimes she’ll welcome him with a smile and small talk. Then there was the time he watched her using one toothbrush to brush another, having seemingly forgotten how to brush her teeth. Or the time she kept asking if the shower was a way out of the room.

But most often, he’ll find her crying, distraught and shaken up by a bad dream she is convinced actually occurred in real life, as she struggles to find the words to explain what she thinks is wrong.

Molly Daley and her son, Joey. Courtesy Joey Daley

"Dementia’s like an onion. You peel off the layers of the memory on the outer layers until you get to the core, where you’re just a child again," Daley said. "It’s suffering to death."

There is currently no way to prevent dementia or stop its advance. There is no "cure." And the only way to even get a definite diagnosis is through autopsy after a patient's death.

About one-third of all Medicare beneficiaries who die in a given year have been diagnosed with Alzheimer’s or another form of dementia, according to 2014 Medicare claims data analyzed by the Alzheimer’s Association. And data from the Lewy Body Dementia Association suggest that the disease may account for up to 25 percent of cases of dementia.

"[Lewy body dementia] is probably the most common disease you’ve never heard of," said Dr. James Galvin, an expert in cognitive health, memory loss, Alzheimer’s disease, Lewy body dementia, and related disorders.

Galvin said the disease is poorly understood and under-studied in comparison to Alzheimer’s, which is due in part to the difficulty in pinning down a diagnosis. A survey from the Lewy Body Dementia Association shows that on average, it took physicians four office visits to make the diagnosis. This lack of knowledge can isolate caregivers further.

“A caregiver is the invisible patient."

To help combat that, Daley created a Facebook group that now has more than 31,000 members, many of whom are caregivers for people with dementia. They use the platform to share stories, seek advice and give out words of encouragement.

Daley helps his mother at his home in Dublin, Ohio. Maddie McGarvey / for NBC News

Periodically, Daley, who is an entrepreneur and works from home, uses the money earned from Molly’s Movement t-shirt sales or donations to organize giveaways for caregivers in the group. The prize is a relaxing night out or, in the case of a 16-year-old girl caring for her grandmother, a shopping trip.

"[The giveaway] is the type of thing my mom would do," he said, adding that he gets about 100 messages every day from people pouring their heart out to him or thanking him for his eye-opening videos.

Any type of support that reduces the feeling of isolation is essential, as caregivers can often forego their own needs when helping dementia patients.

“A caregiver is the invisible patient,” said Dr. Galvin.

But Daley, like many others, shrugs off concern for his own well-being. As his movement grows, so do the demands on his time. The married father of three said he will have to do "more work when everyone’s asleep."

His mother, who was a single parent of two while working two jobs as he was growing up, is his inspiration. One video at a time, he is building her legacy.

As his mother’s dementia gets worse, Daley wonders how much longer he’ll be able to keep recording, especially once she becomes unable to speak. He acknowledges that it will be a delicate balance, something he never got to discuss with her before beginning the series.

"I don’t want to stop early," he said. "I want people to understand how bad it gets."

Daley said the most exhausting part is going over what he recorded at the end of each day, reliving painful moments like the time she forgot he was her son — an event he thought would come much later, perhaps at the end.

But for the many heartbreaking moments, there are still the rare ones when the old Molly shines through, like when she was asked whether she is proud of her son.

"If there wasn’t a Joey, there wouldn’t be me," she answered.