Patti Davis, daughter of president Ronald Reagan, is speaking out about her father’s battle with Alzheimer’s in a new book.

In Floating in the Deep End, published this week, Davis chronicles her relationship with her father, who was officially diagnosed with the disease in 1994 and who died 10 years later. Davis told People that the diagnosis came at a difficult time for her personally in terms of her finances and relationships.

“When this happened I suppose it could have taken me farther down that dark road,” she said. “But it actually had the opposite effect. Because I thought, ‘My father is facing this with such courage and such grace, and my despair paled in comparison to that.’”

Davis’ experience caring for Reagan, who served as president from 1981 to 1989, introduced her to a community of other Alzheimer’s caregivers, which led her to launch the nonprofit Beyond Alzheimer’s in 2011. The new book provides advice for those in similar situations, along with lessons learned from her own experience, especially when it came to mending her relationship with Reagan and her mother, Nancy Reagan.

“The dynamics that were once in place don’t need to define the future,” she writes in the book. “I’d spent so many decades longing for what I was never going to get from my parents. Alzheimer’s made me realize that I had to be the one to change.”

Davis has written numerous books inspired by her life in the Reagan family, including a 1991 roman a clef, A House of Secrets, and a 1992 memoir, The Way I See It.

Mark Athitakis is a journalist in Phoenix who writes about books for the Washington Post, Los Angeles Times, and elsewhere.