At Saturday night's Hotbed Benefit for 10,000 Degrees, a scholarship program for underprivileged college students, Robin Williams's presence was felt everywhere – but especially around the custom-made Pegoretti bicycle donated by the late entertainer for the fundraiser.
"I can see him showing off the bicycle he donated to the auction, getting everyone laughing and raising a lot of money for a cause he cared about deeply," Maxwell Drever, a close friend of Williams's and co-host of the evening, told PEOPLE.
Instead, Drever, whose Drever Family Foundation helps fund 10,000 Degrees, spent time before the event with Williams's widow, artist Susan Schneider, who has been quietly grieving since her husband's death at age 63 on Aug. 11.
"She's surprisingly resilient, and she's looking forward to trying to make something good out of this for others so they don't have to suffer what she and Robin had to go through," said Drever, who held the event at his family's Tiburon, California, estate.
Surrounded by loved ones, including her sister Jean and brother-in-law Rich Horn, "Susan is upbeat and has a positive attitude, but it's very hard for her right now," he added.
Drever's son Galen, another of the evening's co-hosts, called Schneider "an amazing, positive woman. She and Robin loved each other very much – they were always together and just the cutest couple ever. It's hard to lose someone you love. There's not much anyone can say, more than she is coping the best way she can."
Just a month ago, the elder Drever had been celebrating Williams's 63rd birthday with the Oscar winner and Schneider. Delighting in the Moroccan-themed costumes being assembled for the Hotbed Benefit, Williams expressed excitement about the event in his signature free-wheeling style.
"The garage area was set up with all the costumes, and Robin was in there, wearing all these silly outfits, just clowning around," recalled Drever, who shared a weekly beachside yoga session with Williams.
"And yet at the same time, we all know what he was going through. His Parkinson's, that was just one of the aspects that was affecting him," he said. "He had depression, and I have depression in my family, so I had a sense of what was going on. And then to get Parkinson's, and think that maybe you are losing your voice and that you can't ride a bike. ... It was so unfair to him that he would have these things because he has given so much joy and happiness to people."
And he is still, even now, giving back: Williams's bike ended up fetching $20,000 – enough to send two deserving students to college for a year.
Reporting by SUSAN YOUNG