“Sun Seekers ”Author Got to Tell Her Grandfather She Was Writing About Him Before He Died: 'I Know How Much You Love Me' (Exclusive)

The holiday season can be a challenging one for

One author is opening up about how her grandfather inspired her debut novel — and how she got to tell him about about the book just months before he died.

Sun Seekers, the first novel from writer and PEOPLE editor Rachel McRady, tells the story of precocious six-year-old Gracie Lynn, who sets out to break her grandfather John, who has dementia, out of his nursing home. Her mother tells her that when the sun is up, the "worm in his brain" stays asleep, and when the sun goes down, the worm wakes up as a way to explain sundown syndrome, in which patients become more agitated at nighttime.

For the Emmy-winning McRady, the story (which has been nominated in for Best Family Drama at the Zibby Awards) is a personal one — grandpa John is based upon her beloved real-life grandfather, who struggled with dementia for years before he died.

"My grandfather's nickname was Big John, less for his size than his larger-than-life personality. He never met a stranger and dished out compliments like currency," the author tells PEOPLE of the real John Dozier. "He also loved to tell you how much he loved you. In every conversation we had, he'd at some point say: 'Do you know how much I love you?' And I'd reply: 'It can't be as much as I love you.'"

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Despite the love and affection John had for his granddaughter, the way his dementia impacted his mental capacities deeply affecting his relationship with McRady and the rest of their family.

"Though he mercifully never forgot who I was, some conversations went better than others," McRady says, recalling some of the more difficult days with his illness while she was living in London in 2016 — a long ways from the rest of her family and Dozier, who was residing in an assisted living facility in Richmond, Va. at the time.

Neither McRady nor Dozier felt completely at home where they were, she recalls. McRady spent much of her time working alone from her London apartment while her husband was at the office, and her grandfather had been moved to Virginia from his longtime home in Memphis, Tenn. His wife of 73 years and McRady's grandmother Martha had died two years prior.

"I called him nearly every day and sometimes those talks were filled with laughter, memories and love," the author says of their conversations. "Other times, his depression overwhelmed him, leaving him angry and uninterested in living longer. He was 89 and often said to me, 'I'll just make it to 90 and be done.'"

One day, as McRady struggled with isolation in England — "feeling torn about my decision to move abroad" — she picked up the phone to call Dozier. Unfortunately, she had caught him on a "bad day," and his dementia made him behave out-of-character.

"He was angry and hostile, spewing venom at me in a way that the lighthearted grandfather of my childhood never would have. He said all of the most painful words I could have never imagined him saying, leaving me in tears," she says.

"I got off the phone heartsick and angry, not at him, but at the disease that had robbed me of the man I'd known," McRady adds. "I hated that this great man had lived such a full and rich life and that this was his finish line. It seemed like the worst kind of prize."

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"Without really knowing what I was doing, I sat down and began to write," she says. "I wrote and wrote, taking these two on an adventure together, making their last day count. I wrote the ending I wished my own grandfather and I could have. Through Gracie's innocent eyes, I was able to write about a disease that had hurt me and my family so much — three of my four grandparents suffered from dementia in some form or another."

The tale of the worm in grandpa John's brain eventually turned into Sun Seekers.

"I ended with the line, 'At least that's how I wish it had happened. I'd dabbled in writing fiction for years, but I knew that this was my story, the one I was meant to write," McRady continued. "I loved writing in Gracie's unique voice, and seeing the disease through her eyes, but I knew I also needed adults' perspectives, so I added in that of her mother and her estranged father, delving into what Gracie and John's jailbreak might mean to their family and exploring their own trauma."

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As Christmas 2016 rolled around, McRady headed home to the U.S. and stopped in Virginia to visit her grandfather.

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"One afternoon while we were alone, I told him that I was writing a book about him and that I planned to dedicate it to him one day," the author says. "Writing had been a pretty isolated experience for me, one I shared with very few people, so this admission took a decent amount of courage on my part. He broke into a wide grin and gave me a hug, sharing that he couldn't wait to see his name in print."

Two months later, in February 2017, John Dozier died at the age of 89. "I've always been grateful that I was able to tell him before he died," McRady said. "I wrote this book as a love letter to caregivers and advocates, to let them see that they are not alone and to hopefully spread a little light during what is inevitably a challenging time."

"And on the dedication page it reads, 'To my marvelous grandfather John Dozier. Yes, I know how much you loved me.'"

Sun Seekers by Rachel McRady is available now, wherever books are sold.

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