If you've zeroed in the scope for him, he can practice without actually shooting rounds. Just set up 50, 75, and 100 yd targets (whatever ranges you want, really) and he can cycle the bolt on an empty magazine, aim as though there's a live round, and dry fire. He can then see if he's flinching, closing his eye when pulling the trigger, not following through (pulling away the gun/crosshairs right after the shot) and so forth. If he's doing any of these, he can work on it by dry firing a bit. Then you can go to live rounds. Load a round without him seeing if you're actually chambering it. Then hand it to him and let him aim and shoot. Change it up so some shots are a dry fire. That'll show if he's flinching when he thinks there's a live round. This is a lot more effective for younger shooters than just going to the range and shooting a lot of ammo.