I was wondering about draw weight, too. It's hard to tell but it looks as though he may have drawn short by 2" or more. That means that you can deduct 4-6# from the 28" draw weight of the bow. In other words, if the bow is supposed to be 50# he is only getting 44-46# from it. Can he come to full draw and hold it for several seconds without shaking? If not, he needs a lighter bow.
As for missing deer, that could be as simple as forgetting to pick a spot. Not that I've ever been guilty of doing that, mind you.
John