Yep.
All 360 games are also launched retail.
Well not games that are part of xbla arcade aren't. I've never seen a full retail release of resi 4 on the 360 anywhere. As far as I know it's on games on demand but not retail. Although I could be wrong of course. My betting is the version of resi he has downloaded is that version and in that case no it won't work on the xkey