A game like God of War: God of War III. That's all. He won't be able to bear Heavenly Sword or Dante's Inferno. Devil May Cry is slightly different, and pretty good, but no GoW, and Ninja Gaiden can be enjoyable if you enjoy a game repeatedly killing you with small creatures and then rubbing this in your face for fifteen seconds.
As for co-op, ignore everyone saying Army of Two. They are horrible people and should be ashamed of themselves. If he is set on a shooter, Resistance: Fall of Man has great local co-op, and R2 has online co-op which isn't as good. LittleBigPlanet has co-op, which is the best on the console by quite a long way.
If he's willing to go back a gen, 007: Everything or Nothing and Ratchet: Deadlocked have among the best co-op I have ever experienced.
(Former) Lead Moderator and (Eternal) VGC Detective 
