A new documentary is out today On Demand that takes us behind the scenes for a revealing look at what happened to Robin Williams in his final days before he took his own life in 2014.

Robin’s Wish, the untold story, is available for rent or purchase wherever you currently buy movie rentals online, including iTunesAmazon PrimeGoogle Play, and Vudu.

As the filmmakers explain: “Left to speculate on Robin’s motives, the media circus spun out further and further, leaving the public in the dark about a complicated and obscured truth: Robin — bright, funny, quick witted — had lost a battle against an unknown enemy: the nearly impossible to diagnose degenerative brain disease Lewy body dementia. Robin’s Wish is an intimate portrait of Robin in his final days, with deeply personal stories from some of those closest to him, including his wife Susan, who bravely came forward on her own to publicly reveal the findings of Robin’s autopsy — that he had been suffering unimaginably from LBD. Some of Robin’s closest friends and colleagues also speak out for the very first time about what they saw, getting the word out to fans about who Robin really was in light of what happened at the end of his life.”

Susan Schneider Williams says: “During the last year of his life, Robin was confronted with anxiety, paranoia, insomnia, scary altered realities and a roller coaster of hope and despair. With our medical team’s care we chased a relentless parade of symptoms but with very little gain. It wasn’t until after Robin’s passing, in autopsy, that the source of his terror was revealed: he had diffuse Lewy body disease. It was one of the worst cases medical professionals had seen.”

She’ll also be talking about Williams and the film tonight in a live discussion for the American Brain Foundation at 8 p.m. Eastern. You can register for free to listen in here.