A couple of things :
1. If he was a good guy and really did good work. He wouldn't have accepted work we wasn't competent to work on.
2. If he had accepted the work and and in fact jacked things up so badly that the frame required replacement. He should have either sent the weapon back to the factory himself, or been completely upfront with the customer and offered to cover the costs.
If I remember correctly your good guy charged him for damaging the semi-auto, and initially refused to either refund the money charged or pay for the replacement or factory work until the lawyers got involved.
In my opinion this guy, may be nice, but by his actions, doesn't qualify as good, honorable, or competent.
Do unto others....
