The women said their hearts go out to Robin Williams' family.
Robin Williams' 2014 suicide was blamed on depression, but his widow revealed in an interview with ABC that he suffered from Lewy Body Dementia that discovered during his autopsy.
The revelation made by Susan Schneider-Williams that he suffered from the little-known condition has struck a chord with the family of another showbiz legend – Casey Kasem.
Read: Robin Williams Widow Reveals He Had Dementia: I Don't Blame Him One Bit For His Suicide
Kerri and Julie Casem are the daughters of the legendary radio DJ and the iconic host of American Top Forty. He died last year at 82. He also suffered from Lewy Body Dementia.
"To Robin Williams' family, our hearts go out to you. We know exactly what you are going through," Kerri said.
Julie told INSIDE EDITION's Diane McInerney: "His movements were very slow. It was very difficult for him in the last year of his life to dress himself and feed himself."
McInerney asked: "How difficult is it to see a family member suffer from Lewy Body Dementia?"
Kerri replied: "It is hard to watch the person so helpless and so hopeless and scared."
"When somebody can't remember something, or they are fighting for their words, or you can see the frustration in their face ... my dad, his voice was everything to him, and to lose that, I can't image what what going through his head," she said.
Kerri and Julie say Lewy Body Dementia often goes unrecognized.
"It mimics the symptoms of Parkinson's. It is very hard to diagnose," Kerri said.
Read: Freddie Gray's Mother Reportedly Tried to Take Her Own Life
Kerri Kasem now runs an organization called Kasem Cares which campaigns against elder abuse.
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