Any chance your brother was aiming for the vitals, hit the neck, killed the deer, and just said he hit what he was aiming for? Kinda like the " Oh crap..... I meant to do that" mentality? In this case I think it would have been more responsible to state the truth, that it was a shot gone bad that luckily turned out in the end.

It could happen. Just think about the guys who are aiming for the vitals and hit the femoral artery in the back leg and the deer almost goes straight down. (those guys can' t really say that they were aiming for the butt though)