Hard to say what he'll need withour knowing a little more about how, when, and where he'll be hunting. Will he be doing morning and evening hunts where he can walk back to a cabin or vehicle for lunch, or will he be out all day? Close enough to the vehicle to drag one out whole, or will he have to cut it up and put it in a pack?
Sitting on a stand in cold weather it's hard to stay warm, but harder for some than others. Would he benefit from handwarmers for feet and hands?
Regardless, I'd suggest some kind of pack he can put extra clothes, water, and snacks in. A good knife, headlamp, TP, and a little talc squirt bottle to judge wind direction would be minimum for me. And whatever he needs to get his deer out of the woods, drag rope, plastic sled, or if he has to cut it up to haul it out, a couple of large garbage bags to lay the meat on, some game bags, and a decent pack for load hauling.
