Lisa and Peter Marshall were watching a wedding scene on a TV show late last year when he suddenly looked at his wife and exclaimed, "Let's do it!' "

"Do what?" she asked.

When he pointed to the TV, she asked: "Do you want to get married?"

He said yes with a big smile.

"Well, OK — we should get married then," Lisa Marshall recalled telling him.

The next day, she wondered whether her husband would remember asking her, and he didn't. He also didn't remember their first wedding, said Marshall, and for the past six months he has thought of her simply as his favorite caregiver.

Peter Marshall, 56, has early onset Alzheimer's disease, a form of dementia that generally afflicts people in their 30s to 60s and makes up about 10% of Alzheimer's cases overall.

"It's been devastating, but I've done my best to stay positive and focus on one day at a time," said Lisa Marshall, 54, who lives in Andover, Conn. "My mantra has always been to have no regrets."

In January, her husband's mind began declining at a faster pace. And so 20 years after their romance began, with her husband's recent proposal, it seemed like perfect timing to renew their vows, she said.

"It was then that I started thinking, 'Maybe we really ought to do this,' " she said, adding that her daughter, Sarah Brehant, urged her to do it.

Brehant, 32, runs a wedding planning business and told her mom that she'd organize the entire event.

"I knew that my stepdad, who I am very close with, was there through some of the toughest times of my life," Brehant said. "He means so much to me, and my mom is my best friend, so I was proud to be able to take on such an important role."

Brehant contacted a dozen vendors she regularly works with and asked if they'd be interested in making a wedding happen in six weeks, she said.

They all volunteered to help at no cost, she said.

On April 26, as family members and a few friends looked on, Brehant walked her mother to join hands with her stepfather. Officiating the vows was Adrianne DeVivo, a dementia specialist at Hartford Healthcare who helped Lisa Marshall set up a care plan for her husband, and is licensed to perform weddings.

When Lisa Marshall joined her longtime husband at the altar, he leaned in and gave her a kiss.

"It was just magical — straight out of a fairy tale," she said.

"There wasn't a dry eye, and I was over the moon," she said. "I hadn't seen Peter that happy in a long time."

The couple had married in 2009. In 2017, Peter began giving her directions to their own home and he had difficulty finding the words he needed to finish sentences, Lisa Marshall said.

To cope with the daily devastation of watching her husband's memory fade, she started a Facebook blog, Oh Hello Alzheimer's, which she hoped might help other caregivers facing the same challenges. Marshall knows the day is approaching when she might have to place him in a memory care center, but she said she can't think about that yet.

"One day at a time," she said. "I don't know who I am to him now, but I know that he definitely loves me and feels safe."

On difficult days, she remembers what her husband told her as they danced to their favorite song, "Brown-Eyed Girl," after they renewed their wedding vows.

"He whispered in my ear, 'Thank you for staying.' "