Take it with a grain of salt, but I think it's great that he seems interested. You are a lucky dad. I just got back into playing guitar after being away from it for 48 years, but here's my take. As young as he is, I would take him with you to Guitar Center and have the salesman show you some 3/4 size guitars. In order to avoid him not being interested, I would try for nylon string set at first and then switch to steel so his fingers will be ok. There are several guitars at GC that you can pick up for less than 200.00 and if he lets it go and doesn't get interested later on, you are not out that much money. They have several Ibanez packages for around 130.00. Also Fender believe it or not. If you are thinking of electric, I personally own the Keith Urban Night Star solid body electric, and it came with a low action if he wants to start with steel strings. You can also check on 1/2 size guitars while you are there. Hope he does develop an interest. I watched a kid 14 years old playing the Blues with Buddy Guy, and he puts me to shame and I am 64.