For Hellman, though, the entire event wasn’t just so audience members could hear music that he loved; he took the opportunity to form friendships with a community that he had not interacted with much as an investment banker — touring musicians.

As Holliday and others noted, Hellman often referred to the festival as “the most selfish thing” he did every year.

The musicians took to him in spades in spite of the vast gulf of life experience between them and the billionaire.

“That’s the mystery of Warren and I — we’re from different worlds, “ said Jimmie Dale Gilmore, the country singer, who is from West Texas. “But we converged on that one – music -- so much. It opened all the doors.”

According to Heidi Clare, a well-known fiddler and member of the Wronglers, Hellman was constantly subverting notions of what a rich man would be like, picking up hitchhikers and busking on city streets, which endeared him to the musicians. “He is so completely unassuming, he doesn’t play the part in any sense,” Clare said.

“He was seen not as a benefactor but one of them,” said former Chronicle music critic and author Joel Selvin.

“Warren told me once that that he was at a party with Prince Charles and he literally would not walk across the room to shake his hand. But Jimmie Dale Gilmore was a different matter.”

After a brief flirtation with the banjo in his 20s, Hellman took to the instrument in earnest in 2002 when he began lessons. In 2006, at age 72, he made his debut on the Hardly Strictly stage with his band The Wronglers.

The band came into being in an unusual manner when Hellman’s music teacher suggested to Hellman and three other students that they needed to play as a group in order to grow as musicians. To this mix of amateurs Hellman added Clare, the fiddler, his wife Chris and personal assistant Colleen Browne, who happened to be an experienced bass player.

In press accounts Hellman described the first go-round on stage at Hardly Strictly as somewhat disastrous — forgetting the set list, not knowing what key to tune to, omitting an encore — but he kept plugging away.

“The stage manager said, ‘I can give you ten more minutes.’ I said, ‘we don’t know anything else’,” Hellman said in a video interview earlier this year.

In 2011, the Wronglers established that they were more than a practice band for Hellman. With Jimmie Dale Gilmore at the helm, they released an album called “Heirloom Music,” showcasing traditional American songs from the 30s and 40s.

The album’s launch set the stage for the last chapter in Hellman’s journey through the music world: as a touring band member. The Wronglers hit the road this spring and summer, with Hellman travelling like any road musician, in a bus.

“He loved the touring,” said Gilmore, “In a small way, we were able to give back a little of what he gave.”

The Wronglers held their last practice at 5 p.m on Tuesday, after Hellman returned home briefly from the hospital. In the small basement room lined by artworks by Hellman’s wife, the band, minus Gilmore and two others, gathered.

“He didn’t look that happy, he was mustering every bit of strength,” said Clare, “After a half an hour, I asked if we should stop. He looked at me, and said, well, how long has it been?”

It had not been the full hour. Hellman insisted they continue.

“He played so well that evening, it blew my mind. I mean, not just well for his condition – he played really well,” Clare said.

“We ended with a song we’ve never performed, ‘Big Twang Theory.’ We all said, wow that was fun, that was good. And he had a beautiful smile.”