If he just wants to get used to shooting honestly a .22 rifle is pretty good. You can get snapped in on how it feels to shoot and operate safely without going blind on the cost ammo. Also if something goes wrong, it's going to do a lot less damage potentially than say a 30-06. Where I come from (upper midwest farm) .22 a lot of kids first weapon. Otherwise I would base it on what he wants to use it for. For home defense, pistols can be difficult to master for a lot of people especially if you don't shoot regularly. But they are a lot of fun at the range. A 12 gauge with 00 buckshot is easy to use, incredibly effective for home defense, and won't travel through every wall in your house when you shoot it. It's not much fun on the range though.