During the show's panel discussion, Maher began by praising Biden for his remarks on the coronavirus outbreak following President Trump's much-criticized Oval Office address.
But Maher insisted that Biden continue to act as a "shadow president" since "we don't have a real one."
The comedian later pivoted to Tuesday's primary elections, where he acknowledged Biden has been "kicking ass" in the primaries.
"There's going to be a debate on Sunday, they moved it to Washington, and there's no live audience -- barely two live candidates," Maher joked. "What are they debating about at this point? Why are we having this exercise? Because I feel like it can only hurt Uncle Joe, which plainly, look, I know he could do the job, but he's a little cuckoo himself."
The HBO star pointed to the altercation Biden had with the Detroit autoworker over his stance on guns and when Biden threatened to "slap" the worker.
"His big go-to is, 'You wanna fight?' Who's 78 and every time there's an argument, it's like, 'You wanna take it outside?'" Maher exclaimed. "Passionate is one thing, but challenging people to fights is like, roid rage. It's wrong."
"His big go-to is, 'You wanna fight?' Who's 78 and every time there's an argument, it's like, 'You wanna take it outside?' Passionate is one thing, but challenging people to fights is like, roid rage. It's wrong."
Maher also pointed to the incident where Biden mixed up his wife and his sister at a rally, telling the panel that he "sounds like a guy who "always coming to from being knocked out."
During Maher's "New Rules" segment, the host went after Biden for the way he smiled.
"New Rule: Joe Biden has to stop smiling in a way that makes it look like he's already had a stroke.
"Look, just make it until November," Maher added. "Then you can have all the strokes you want."