Definately have a right to be mad. I am.. A friend of mine is trying to get into bowhunting this year and I flat out told him I wasn't gonna let him hunt until he can shoot comfortably from 20, consistantly. He was fine with that. That stinks that you have to treat your friend like that, but, hey, he deserves any whooping that you give him! Give him one for me too, will ya?
Hopefully, like others have said, he learns from this and becomes smarter and a better shooter because of it.
We all have probably lost a deer or two, but what he did was just stupid...
Good luck!!