what a horrible story... but if you think about it, its a bit funny. maybe i just have a bad sense of humor?
anyway,,, i think the Wii is a great choice. I have to admit im a little gamer, and looking at how old your boys are. i think the Wii would be an easier system for them to learn how to play.
+plus: it sounds like you want to stay away from shooting/killing games, and nintendo doesnt have a lot of those. and you could hold off on the numchuck for now if you want, not all games require it. you could always buy it later. but you will want to buy another remote. and make sure whatever games you do buy are for 2 or more players.