Hello! I hope I can help with your questions!
In order to make him feel more comfortable, I would bring up topics that everyone has in common.
Medium - maybe 15-20 people I'd guess.
Hmm, I'll have to think about that - most of my friends are parents, he isn't.
Alright, I'm sure I can think of something.
Well, is it appropriate for me to leave him to talk to other people at the party if he seems comfortable or should I stay near him?
Yeah, he seems pretty outgoing though I haven't had much opportunity to observe him in groups. Thank you for your help!