Reagan’s doctors and Alzheimer’s specialists have been debunking this myth for years, but no matter how many times they try to explain that occasional memory lapses in an elderly person do not an Alzheimer’s diagnosis make, the narrative rolls on. And it’ll keep rolling, thanks to Ron Jr and the explosive never-before-revealed details in his new book which, per Paul Bedard of U.S. News, … seem not to add up.

Besides playing amateur doctor, Ron Reagan reveals, if true, brain surgery on his dad never before reported. He accurately reports that Reagan, after leaving the presidency, was bucked from a horse on July 4, 1989, while in Mexico. Ron tells of how his dad, after initially refusing medical help, was transported to a San Diego hospital. “Surgeons opening his skull to relieve pressure on the brain emerged from the operating room with the news that they had detected what they took to be probable signs of Alzheimer’s disease.” Several Reagan associates, however, say there was no surgery in San Diego.

What’s more there is no reporting about any San Diego operation on Reagan. News reports at the time of his fall say Reagan was flown to a hospital in Arizona, where he was treated for scrapes and bruises and released after five hours…

Ron Reagan doesn’t mention this, but says that Reagan visited the Mayo Clinic in 1990 for tests that “confirmed the initial suspicion of Alzheimer’s.” Reagan’s post-presidency history, documented in several archives like University of Texas, reveal no such visit. And Dr. John E. Hutton Jr. his doctor from 1984 through Reagan’s retirement, told the New York Times that Reagan didn’t show the tell-tale symptoms until 1993.

Follow the link and you’ll see that another big piece of “evidence” is Ron feeling his heart sink as he watched his pop stumble through a bad, “bewildered” performance in his first debate with Mondale in 1984. Quote: “Some voters were beginning to imagine grandpa—who can never find his reading glasses—in charge of a bristling nuclear arsenal, and it was making them nervous. Worse, my father now seemed to be giving them legitimate reason for concern.” That was October 7, 1984; a month later, the “concern” had turned into a 49-state landslide.

Here’s former Reagan advisor David Gergen telling Ron, as gently as he can: Stop.