Was what he was asking of me unreasonable?

His immaturity and low self esteem/self confidence are the only plausible reasons for him reacting like you said... and the fact he focuses on finding fault with you only supplants that thought process...and the fact that you showed maturity in answering their questions, etc...bodes well for your own self confidence and self esteem which is probably still developing...he needs to come to grips with his own behavior and insecurities....if he can not...don't let him impose them on your life...