Dial,
The good news about your anxiety provoking story is that your DS got an early experience in what will happen over and over again both in the military and in civilian professional life.
I do tell the story about how my son did so poorly in his FFR interview that he was told to "improve your eye contact, and while your at it retake your ACTs"
The interviewers, though, on the MOC nomination committee are constituents who are in some way affiliated with the military (served or family members) they are NOT necessarily people with social skills or interpersonal skills. It sounds like your son weathered it just fine.
Keep us informed, I always love to hear about others from the Land of Lincoln.
Good luck!