EXCLUSIVE: Michael Reagan Rejects Half-Brother's Charge Their Father Had Alzheimer's While President

USA Today reports...In a new book -- and an interview on ABC's 20/20 -- President Ronald Reagan's son says he saw evidence of his father's Alzheimer's disease back during his years in the White House. "There was just something that was off, I couldn't quite put my finger on it," Ron Reagan said in 20/20 interview airing Friday night. The younger Reagan said his father often didn't seem sharp during their political debates. At another point, Ron Reagan saw his father read from not[e] cards as he made phone calls. "It wasn't like oh my God he doesn't remember he's President," Reagan said. "You know, it was just -- I had an inkling something was going on."

Michael Reagan released the following statement to FoxNation.com: "Ron was an embarrassment to his father when he was alive and today he became an embarrassment to his mother."