I haven't done too much training with him yet. I've been mostly concentrating on getting him over his shyness and not putting too much pressure on him.
He has never bitten anyone else... that's why it surprised me so much
Yes, he is willing to work with him. This is a very new relationship and my dog (Dutch) had never met him before yesterday
30 lbs or so
I've never seen signs of aggression outside the home (shyness, yes, but never growling, etc)
This is the first time this had happened, but the way I dealt with it was to correct him with a choke collar and say NO! loudly and put him in the other room.