LoL would say this as all I've seen on the internet from this is running about, attaching lines to things and making them spin round and round (think 747 going round a bridge xD ). I remember Soldier of Fortune had option to turn off blood/gore, quite funny going from blood everywhere and being able to shoot off bits of peoples heads at a time to just having a bright spark hit marker like you're shooting flint at a rock xD
I'm pretty glad that you and the misses think 8 is too young for the likes of GTA and such. hell i think the most violent game at a young age I played was roadrash at like 12 or something and that's more arcade racing with the ability to bop people off their bikes.
so yea as stated, minecraft is a good run about game, any of the fallout/skyrim series is worth an adventure. what about letting him play arma3 if he likes the look of it? you can play offline missions with AI and they are releasing their story bit by bit. can also turn down/off the blood. don't think there's any swearing in it......maybe dayz?

could play that single player (if possible?) so massive world, survive zombies and exploration?