It's been almost four-years since Robin Williams' tragic suicide and not a day goes by that Hollywood doesn't feel the gravity of his loss. That said, the more time that passes, the clearer it becomes that the late 63-year-old was sadly struggling with a number of demons, some of which were seemingly too far beyond anyone's control or ability to fix.

In an excerpt from the new book Robin by Dave Itzkoff — obtained by the New York Post Robin's former makeup artist, Cheri Minns, recalled just how inconsolable the actor was in his final days, particularly on the set of Night of the Museum: Secret of the Tomb. “He was sobbing in my arms at the end of every day. It was horrible. Horrible. I said to his people, ‘I’m a makeup artist. I don’t have the capacity to deal with what’s happening to him.'”

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Cheri suggested that Robin return to stand-up comedy, hoping it would restore his confidence and good spirits. Unfortunately, he refused. "He just cried and said, 'I can’t, Cheri. I don’t know how anymore. I don’t know how to be funny.'"

Cheri is hardly the only person to have noticed a shift in Robin's personality toward the end of his life. With pressure mounting over his expensive divorces, declining career, and health, Robin ultimately felt unable to hide his torment behind a mask of manic merriment. "If you looked close," Ed Asner, who guest-starred on Robin’s final TV series, The Crazy Ones, once exclusively told Closer Weekly, "you could see someone who was terribly afraid."

robin williams final days

Despite being unable to prevent the tragedy that happened, his friends and loved ones continue to try and understand his ultimate demise. “I put myself in his place. Think of it this way: The speed at which the comedy came is the speed at which the terrors came,” Cheri recalled in the book. “And all that they described that can happen with this psychosis, if that’s the right word — the hallucinations, the images, the terror — coming at the speed his comedy came at, maybe even faster, I can’t imagine living like that.”