As far as bad shots, or an unrecovered animal, it happens to all of us, regardles of what type of bow.
I teach at Camp Wilderness here in MI, we run a combo Hunter Safety/IBEP program for youth. What we teach, is the IBEP thought htat whomever puts the killing shot on the animal is the one who should claim it. If he had put a killing shot, but you had the opportunity to finish it and put the animal down wuicker, it would e his deer.A non-lethal hit, followed by your lethal shot, and its your deer. Its known by IBEP as the unwritten rule.
That aside, we never encourage an arguement or the like over an animal. Keeping peasce in the family is important too, and it sounds to me like you've had the thrill of taking some nice animals, and allowing him this one was a generous gesture.
I would however talk to him about proper shot selection, wht he considers a proper shot angle and distance. If its not within what you prefer, then I would tell him those are the rules on your place and if he doesnt respect them, the opportunity to hunt there will be gone.
I have a nephew who is what I call a shooter rather than a hunter, and he will shoot at less than ideal angles/distances before he will pass a shot. My wife keeps bugging me to bring him up to our camp, but until his attitude changes inthat regard, it wont happen.