Plus: Jerry Seinfeld and Joan Rivers recall their unsentimental friend

Despite his gruff stage persona, offstage the late George Carlin was a gentleman who showed kindness to strangers and offered a hand to others hoping to beat addiction problems, Tom Arnold and other comics tell PEOPLE – while Jerry Seinfeld and Joan Rivers are expressing their appreciation of their unsentimental friend.

“Several times he’d call young comics who were messed up on drugs, and just introduce himself as ‘George, a recovering addict, and why don’t you go to a meeting with me or we can get together and talk,’ ” says Arnold, 49, who’s also battled with drugs and alcohol. “And it blew them away. Nobody said no.”

Arnold and those other comics who worked alongside Carlin over the decades made their remarks Monday night at Hollywood’s the Laugh Factory, during a taping of Supreme Court of Comedy. Carlin, 71, died of heart failure Sunday.

“He was a real gentleman, a great guy and a much better person than he pretended to be,” says comic Dom Irrera.

Several comedy figures, including Ben Stiller and Jay Leno, have publicly cited Carlin’s influence on humor. On Tuesday, Jerry Seinfeld, in an op-ed piece in The New York Times, notes that Carlin’s authority could also be a stumbling block to others in the field.

“I couldn’t even count the number of times I’ve been standing around with some comedians and someone talks about some idea for a joke and another comedian would say, ‘Carlin does it,’ ” Seinfeld writes in his appreciation. “I’ve heard it my whole career: ‘Carlin does it,’ ‘Carlin already did it,’ ‘Carlin did it eight years ago.’ ”

Still, went the sentiment at the Laugh Factory, Carlin for many years served as a mentor to young comics mesmerized by his wit and mastery of the language, said those who gathered. He also was keenly aware of his own limits.

Comic Paul Rodriguez recalled running into Carlin at a sushi bar two years ago, following Carlin’s stint in rehab for a Vicodin-and-wine habit.

“He said, ‘I have a lot of work to do, I have to go back and hear all the s— that I wrote [under the influence] and see if I meant any of it,’ ” Rodriguez remembered.

Several others recalled Carlin’s taste for marijuana. Recounted comic Paul Mooney: “Richard Pryor would say: ‘He’s a big pothead, but he’s a very funny white boy.’ And I know he and Richard are up in heaven now, talking and smoking a blunt.”

Joan Rivers, writing in Tuesday’s New York Post, may not agree with that last statement.

“He wasn’t sentimental,” she writes. (Seinfeld flat out states, “George didn’t believe in heaven or hell. Like death, they were just more comedy premises.”)

“But don’t kid yourself,” adds Rivers, “he would have loved all the attention he’s getting right now. Just don’t say that he ‘passed away.’ ‘Passed to where?’ he would ask.”

HBO, Carlin’s TV home for three decades, has announced a marathon of his comedy specials, starting with five shows Wednesday on HBO2; Thursday will bring six more on HBO2; Friday, his final special, George Carlin: It’s Bad For Ya, on HBO; and Saturday, 11 hours of specials on HBO Comedy. Check local listings for times