A 12 ga is fine for someone that's become comfortable with recoil.
Not a raw beginner.
I would disagree with this. First, you can get low recoil loads which is all you need for HD. Most 2 3/4in bird (read: practice) loads don't have a whole lot of recoil. Second, there isn't much more of a simple gun than a pump action shotgun. It's easier to aim and control than a handgun, and can be used for HD as well as a woods defense gun (Mine was primarily a bear gun).
Granted, a little training can go a long way, and a handgun might have been a better way to go in the long run. But if this guy had no intention of seeking more than basic instruction, the shotgun will be fine for him. Though, I might have steered towards a 20ga if one had been available.