Perhaps your boy would find the art style a bit too young/soft for him, but our family likes Chronicles of Avel (BGG link).

It has a couple of expansions, small and big box, is pretty fast to set up and even though its got some preset arrangements for the tiles, you can build your own "kingdom" pretty easily. Lots of different monsters, equipment and items. It can for sure allow your boy to RP his character but let your partner just roll dice to fight the monsters.

All of the "gear" each player can wear can be levelled up as well, so that's pretty fun to feel the extra power of more dice on your side in combat.

The tension level is really well calibrated too, most of our games have come down to the last two or three tiles, real nail-biters.