I've also got an 11 year old who loved Fallout 3; which I disabled the gore on, and despite the games unusual nature its fairly mild without the gore. However I got him New Vegas for christmas and I decided to install it early so it would be ready to play on christmas day for him and to tweak the graphics options and disable the gore; since you can't disable the gore I wouldn't feel right letting him play it and blood/gore in games and movies is not approved of in my household (not to mention I don't particularly like playing it with gore on either).
Can anyone help to find a way to disable the gore? Maybe someone knows of another working mod?