David, 66, revealed Monday he is suffering from dementia, and told PEOPLE that while he is Katie’s biological father, he didn’t raise her. Katie was born in 1986 to model Sherry Williams who had a brief romance with the pop star.
"I’ve never had a relationship with her," Cassidy said of his daughter. "I wasn’t her father. I was her biological father but I didn’t raise her."
"She has a completely different life," he added.
However, it is a completely different story when it comes to his only son Beau, 26.
"He’s just one of the best people you’ll ever meet in your life and it’s that that I’m proud of," Cassidy said.
Beau is his son from his third marriage to Sue Shifrin. The couple married in 1991, the year their son was born. In 2014, Shifrin filed for divorce.
The former star of The Partridge Family, who became a teen hearthtrob sensation in the early 1970s, said his son knew of his dementia diagnosis and is supportive.
Cassidy revealed his illness after a shocking performance on stage at the Canyon Club in Agoura Hills, just outside Los Angeles, on Saturday night during which he forgot lyrics, slurred his words and at one point fell over.
His mother, the actress Evelyn Ward, struggled with dementia until her death at 89 in 2012. His grandfather also suffered from the memory loss disease.
[H/T Daily Mail]