hehehehe,,, I sense a good experiment and/or wager in this
switch games for a week, really simple. You play his games only (Halo, CoD etc) and he plays your games only for the entirety of that week... the first ones to go back to his/her games loses.... it could broaden both of your horizons in the end...
I tend to prefer simpler games as well, which may not be rated M.... sometimes, yeah, I want to see blood, but most M rated games today seem to be the same with their awesome graphics... but they often lack in gameplay...
also... you have the upper hand in that one, as he has to miss out on his online friends it's win/win.