Comedian Robin William's death in 2014 is one of the most devastating things to ever happen in Hollywood. Nobody knew that he was suffering emotionally and psychologically. 

Robin's spouse, Susan Schneider Williams, has revealed that doctors ordered them to sleep separately because the actor suffered insomnia. 

Speaking on the documentary "Robin's Wish," "He said to me, 'Does this mean we're separated?' Schneider shared. 

Calling it a challenging and shocking moment, she added, "When your best friend, your partner, you love - you realize that there's a giant chasm somewhere, and you can't see where it is but that's just not based in reality."

Robin Williams and his third spouse Susan Schneider met at an Apple store in Corte Madera, California, in 2007. 

Weeks before the "Mrs. Doubtfire" actor took his own life, Schneider revealed to USA Today in 2014 that Williams surprised his wife at that same Apple store bearing flowers. 

"I looked at him, 'Oh my God, what are you doing?' And he said, 'This is where it all began."

Robin Williams had a kind and gentle spirit, and he is loved for his hilarious and heartwarming portrayals in movies such as "Dead Poets Society," Good Will Hunting," and "Aladdin."

Unfortunately, his sweetness was masked with his battles as the actor struggled with depression, drug, and alcohol addiction. 

Reportedly, the cause of it all is Lewy body dementia, a rare degenerative neurological disorder that left Robin Williams impaired, frustrated and confused. 

"Robin's Wish" will talk about the actor's final days and his battle with the disease, as well as paranoia and hallucinations - all of which are said to be brought on by Parkinson's, the diagnosis he received just three months before Robin Williams' death. 

Like Parkinson's and Alzheimer's, Lewy body dementia robs patients of their motor skills and cognition. However, it typically progresses quickly, making problem-solving and comprehension hard to understand for those affected. 

Schneider, who serves as the Vice-Chair of American Brain Foundation, said, "He was the bravest man in the world, playing the hardest role of his life."

"For someone as brave as Robin, who put his heart and soul into his career, to just start losing the abilities.. it was devastating for him to watch what it means to be human slipping through his fingers." 

Speaking to TODAY's Hoda Kotb, Schneider also explained that Robin told him all he wants is to reboot his brain. 

"At that moment, I promised him that we would get to the bottom of this, and I just didn't know what would be after he passed." 

She further said that it relieved her that finding out what led to Robin Williams' death helped her put some puzzle pieces together.

"Robin and I had gone through this experience together, really chased by an invisible monster. I left there with the disease's name, the thing that Robin and I had been searching for." 

On August 2014, at the age of 63, Robin Williams took his own life by hanging.

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