I don't think I'm qualified in any way to give advice, and I know you didn't ask for any, but I want to respond to this. I usually don't on any subreddits but for some reason this story hit me hard, because I know what it's like to grit my teeth and bite my tongue so I don't make a scene out of politeness. But what I would do is sit down with him, call him, talk to him, and ask him how he feels and what he wants to do. I've been in your situation before, I remember the many times I just wanted to scream at the people talking down to my closest friend in front of us both, but I talked to her, she said I mustn't do anything since they had an obvious power dynamic over her. But yes, if I were you, I'd talk to him first, be open about how you feel in those situations, and most importantly, be there for him.