You coming here with these questions is really sweet. Understand that some people who stutter but seem to remain cool and calm may still have strong feelings about something. I 'learned' early how to hide my frustration from people around me. I've been married for 9 years and it's just becoming clear to my wife how strong my temper can be (reasons for this are not relevant to stuttering currently). Try to be open to him expressing his feelings - especially the unpleasant ones. It's important for people to be heard in this regard. And you sounds like a good person, I wish you the best.