If you live in a metro area, there are plenty of poor musicians that can help guide your son learn rock guitar. I doubt there is any formal school for it even today. Most rock players learn chords, then learn how to play lead around the chords. And I suspect that almost all great guitars are self-taught. The hardest part about starting out on guitar is keeping the darn thing in tune. Or for that matter, even deciding which tuning to use. But voila! Today they have electronic tuners for like $20!
Anyway, learn the E A B7 chords and you can play a couple thousand blues songs. Heck, I had a hard time figuring out how to play "Spoonful" Why? It is ONE chord! So if you use the Nashville chord system E A B is 1, 4, 5. Throw in the 2 and you are really humming that would be E F# A B7. F# is a little more difficult because the best way to play it as a barre chord. But barre chords aren't that tough on a decent electric.
Stevie Ray Vaughan actually raised the action on his guitar, making it "harder" to play. Why? Because he got a richer tone. Playing blues and rock is all about tone. (and bending the strings and all that) and just having that blues in your soul. You either got that or you don't. It dannot be learned or taught.
But don't worry Boomerang a lot of this is recessive genes.
BTW the song Lovesick Blues popularized by Hank Williams but taught to him by the guy who showed him how to play contains every chord a blues guitar player ever needs to know.