Quoted from RonB:My recommendation to you is to take your son to an arcade or pinball show and see what he is drawn to other than trying to 'guess' what he'll like/play.
I agree about introducing your son to many pinballs... I think going to an arcade maybe difficult to get his attention focused just on pinball, with many other games there too.
Idea: Maybe you could post an ad in your local Criagslist, asking for local pinheads to invite you over to their home collection to test some games. I know I would be very happy to accommodate a request like that in my town.
Kerry