No models in Forza so your all good to go there.
I'm guessing they don't let him play shooters so scratch ODST, L4D2 and MW2 off the list. I've heard Viva Pinata is good if he doesn't have it yet and you can find it cheap. Then theres Rockband or Guitar Hero. Maybe Halo Wars if he likes RTS games although there is some violence in the game but no noticeable blood or anything major. In the end you could just go with Onyxmeths suggestion and just get him the latest release of a sports franchise game that he likes.
The definitive evidence that video games turn people into mass murderers








