Do you know which ones he already has?
You can always go with some of the popular ones like
Field and Stream, Outdoor Life, Petersons Bow Hunting or Deer and Deer hunting.
Check out this link. You can find alot. If you know his particular interest pretty well go with a magazine that targets it. For example his bow hunting or deer hunting interest. Field and Stream and OUtdoor Life are pretty broad based.
Bowhunting Magazine Subscription - Hunting & Fishing - Magazines.com Magazine Subscriptions