“Quite often when he opens his mouth a slur of unrelated words come out, like a dozen different false starts tangled together, from which an actual sentence eventually finds its way out. For example, ‘So/Now/And then/Well/It/I – Sometimes I used to work just to work.’ It's like trying to tune into a long-wave radio station,” The Guardian reported in 2010.

Prior to that Williams was 20 years sober. Following years of cocaine and alcohol abuse he went cold turkey after the death of his friend and former comic, John Belushi and before the birth of his son, Zachery. Belushi overdosed on a “speedball” of cocaine and heroin at LA’s infamous Chateau Marmont hotel in 1982 following a night out with Williams and Robert De Niro.

“I didn’t have to join a group. Zach was about to be born and I didn’t want to miss it because I was coked up or drinking. It was hideous enough feeling hungover, without a baby screaming. I mean, there are times when you think ‘God made babies cute so you don’t eat them’, imagine if you’re loaded,” he told The Age in 1994.

Zachery was his first and only child from his first marriage to Valerie Velardi. The couple were married for 10 years and divorced in 1988. However in 1986 Williams was sued by a mistress whom he infected with herpes. He was ordered to pay the woman, a cocktail waitress, $6.7 million in damages.

The Good Morning Vietnam star then married Zachery’s nanny, Marsha Garces, in early 1989 when Garces was pregnant with his second child – avid gamer and actress, Zelda. The couple then welcomed son Cody, Williams’ third child, in 1991. The pair also worked together on many of Williams’ film projects in the ‘90s. Not only was she his assistant but Garces also produced one of his most memorable films, 1993’s Mrs Doubtfire.

After 19 years together, Williams and Garces divorced in 2008. His relapse with alcohol while shooting on location in Alaska in 2003 was the beginning of the end for the couple and for his long-term sobriety.

“I was in a small town where it's not the edge of the world, but you can see it from there, and then I thought: drinking. I just thought, hey, maybe drinking will help. Because I felt alone and afraid. It was that thing of working so much, and going f---, maybe that will help. And it was the worst thing in the world,” he told The Guardian.

His family intervened before he sought professional help for alcoholism in 2006 and spent two months in a facility he called “club medicated”.

He claimed he never dabbled in anything harder than Jack Daniels (by the bottle) after 1982. Even though he once said, “Cocaine is God’s way of telling you that you’re earning too much”, after Belushi’s fatal overdose he was vocal about the perils of drug addiction.

“No. Cocaine – paranoid and impotent, what fun. There was no bit of me thinking, 'ooh, let's go back to that'. Useless conversations until midnight, waking up at dawn feeling like a vampire on a day pass. No,” he said.

Following his treatment, his second divorce was finalised. Both marriage breakdowns reportedly cost the comedian more than $20 million in settlements.

“Divorce is expensive. I used to joke they were going to call it ‘all the money,’ but they changed it to ‘alimony.’ It’s ripping your heart out through your wallet. Are things good with my exes? Yes. But do I need that lifestyle? No,” he told Parade magazine in 2013.

In 2011 he married graphic designer Susan Schneider after they met in 2009. Schneider, 48, nursed him back to health after he underwent major heart surgery in 2009. They married in front of close friends, including Billy Crystal and George Lucas, in an intimate ceremony in the Napa Valley before honeymooning in Paris.

Despite a happy home and a full schedule of work, the 62-year-old returned to rehab in July this year. The visit to a clinic in Minnesota was reportedly planned and seen as an opportunity to relax and reconnect with the 12-step program.

His publicist Mara Buxbaun said at the time the actor was “taking the opportunity to fine-tune and focus on his continued commitment, of which he remains extremely proud.”

While Williams will be remembered for his film and comedic legacy, his enduring friendships are the stuff of legend.

After Superman star Christopher Reeve was paralysed in 1995 from a horse riding incident, Williams pledged to pay the actor’s medical bills. The pair studied at New York’s Julliard School in the 1970s and made a pledge that whoever made it big first would help the other. At the time Williams was worth $135 million according to the Daily Star.

However his charity, kindness and proclivity for divorces forced him back to Hollywood in 2013. He picked up a regular TV role, his first in nearly 30 years, alongside Buffy star Sarah Michelle Gellar in a comedy called The Crazy Ones.

“The idea of having a steady job is appealing. I have two [other] choices: go on the road doing stand-up, or do small, independent movies working almost for scale [minimum union pay]. The movies are good, but a lot of times they don’t even have distribution... There are bills to pay. My life has downsized, in a good way,” he said in one of his final interviews in September 2013.

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