In my opinion, definitely. People are gonna be douchebags like that, sure. But if I had anything to do about it I'd tell them to leave him alone, and I'd leave the restaurant and find another. (I'd want to speak to the manager as well, but that's just me. I'd get that asshat fired.) If you know that it hurts your friend, then protect him when you can, because no one deserves to be treated like that, especially if they've already had a long day. If he mentions that he doesn't appreciate your defense afterwards, then don't, definitely! But if he hasn't said anything at all, he could be internalizing it. Always say something when people are beating others down for something they can't control. Best of luck!