'Why Is This Happening to You, Mom?' A Look Back at Kimberly Williams-Paisley's Emotional Book About Her Mother's Struggle with Dementia

Kimberly Williams-Paisley’s mother, Linda Payne Williams, died Wednesday after a long battle with dementia. She was 73.

The Father of the Bride star recently chronicled her family’s journey with her mother’s dementia in her candid memoir, Where the Light Gets In: Losing My Mother Only to Find Her Again. Williams-Paisley spoke about her mom and her memoir with PEOPLE in the article below, first published on March 30, 2015.

Kimberly Williams-Paisley started noticing odd changes in her mother’s behavior when she got engaged to country superstar Brad Paisley in 2002.

When the Father of the Bride actress excitedly told her mother, Linda Williams, that she was getting married, she was met, in part, with silence – not exactly the reaction Williams-Paisley expected, she tells PEOPLE.

“We are such a close family and I was the first kid to get engaged and I thought, ‘That’s what it is,’ ” says Williams-Paisley.

After she and Paisley wed in 2003, her mother embraced her son-in-law wholeheartedly, but continued acting in ways her family had never seen before. She began mispronouncing words and showing frequent signs of confusion – like the time she asked if she could order nachos at Starbucks. Williams-Paisley says she, her father, Gurney, her sister, Something Borrowed actress Ashley Williams, and brother, Jay Williams, “knew that something was up.”

(L-R) Kimberly Williams-Paisley; her mom, Lynn Williams; and her sister, Ashley Williams.

In 2005, they learned that her mother, then 62, was suffering from a rare and incurable form of early-onset dementia called primary progressive aphasia, which left her moody, accident-prone and increasingly unable to recognize her own family.

In her poignant new book, Where the Light Gets In: Losing My Mother Only to Find Her Again, out April 5, Williams-Paisley details her family’s difficult journey – including the mistakes they made along the way – as they bonded together, trying to help her mother as best they could.

During one touching visit at the long-term care facility where her mother, now 72, lives, the actress writes that she often asks, Why is this happening to you, Mom?

One of the highlights of the book is how Williams-Paisley, 44, learned to embrace the woman her mother has become. “It was really important to me to have the silver linings and the positives in it,” she says.

The book also provides a list of resources, such as where to get information and help for caregivers, which Williams-Paisley hopes will help others who are dealing with dementia. “That motivates me more than anything,” says Williams-Paisley, who is a spokeswoman for the Alzheimer’s Association. (Alzheimer’s is a form of dementia.)

Since her mother had asked her and her family to keep her dementia private for years, out of embarrassment, Williams-Paisley says, “Unfortunately, we missed out on a lot of resources we could have gotten. But we were doing the best we could. Helping other people just makes me feel really proactive.”

For more information, visit WhereTheLightGetsInbook.com and alz.org.