If you're making the argument that games aren't all shooty-killy, I'd definitely avoid FPSs (and also agree that they can be difficult for a new gamer). I'm assuming since you're even having this discussion, that he is at least somewhat familiar with games so my suggestions are a little off the wall.
First, an oldschool PC game called Black & White. It is one of Peter Molyneux's older franchises and is basically a God Game where you train a giant pet to be either good or evil. The gameplay is pretty good, but not awesome though and it might be hard to find.
Second, Thief 1 or 2. They involve some killing, but it can definitely be avoided in most situations. The games leak atmosphere out of every pore and the stories are simple, but not stupid. Problems are that it is first person and can be violent though.
Lastly, World of Warcraft. Combine the problems from the Thief games and x100, but as a Pally or Druid, he should be able to solo pretty well, enjoy the story of the questlines, and get addicted to loot (worked on my Dad). Like I said though, lots of mindless killing, which might be a turnoff.
I suggested all PC games because they have a lower barrier to entry than console games since most people are already familar with mouse and keyboard controls, which might be better than a cold start with a controller.
Good luck!
