Of course you can win against them. That's why they're called terrible and not good.

However, the subtext might be that your buddy can't play a style of poker that is fun for him to play and still win against these guys. Maybe one of the reason he finds your home SnGs fun is that he can put moves on people and beat players he considers good. If that's the case, you might actually want to consider not bringing the guy back, or at least educating him a little.