If your son likes music with electric guitar, have him play the electric. Having self-taught myself how to play guitar (never had lessons and it shows!!
), a lot of difficulty in the beginning is getting through that "I can't play anything" phase. I would suggest sprinkling in easy songs to play or easy versions of songs that your son likes with formal lessons. Some people recoil at the thought of tablature, but it can be a fun shortcut to learning songs.
Playing guitar should be all about having fun. If you're not having fun, you're not doing it right.