the problem with writing bullet points is that you're assuming he gets so nervous that he forgets his talking points. Being introvert isn't about being forgetful/bad under pressure, it's just the lack wanting to present outward socially. Getting him accustomed to large gathers where he can talk with people comfortably would be the best thing to practice because it helps with the rest of his career and not just answering questions. Sign him up for a speech class, giving a dozen, or couple dozen speeches to a "crowd" will do wonders for him. Make sure it isn't to "family/friends" because he is comfortable around them. Push his limits with a crowd of strangers and he'll learn that his fear is only in his head because they don't actually "know" him, they only know what is being presented. Once he learns how to "present", then the rest is becoming familiar with the people.
Sure, I won't ever be the highlight of a social gathering, but if the spot light is pointed at me, I can do well enough until it passes to the next person. I'm a bad car salesman (bad at bsing people) but I'm a likeable person once people get to know me, this is what he has to learn. To be able to sell himself to people to get the shot at being liked by them.
the rest of the things people say are just covering up his lack of social skills. Bad eye contact, unsure how much to say, etc. He doesn't need to be bubbly, or to overshare. But he should know how to give a presentation that isn't awkward. Not an award winning one, but one that doesn't make the audience feel pity on him, you know what I mean hopefully.
http://www.ethos3.com/2014/11/presen...nd-extroverts/