The best advice I could give is get your son to a shoot and let him try out a few different bows. Longbows can vary a LOT in design, and what one person loves another may hate. I love longbows, and shoot one 99% of the time (the only exception is when I go bowfishing), but there are some that I just don't like. Lots of great ones on the market, and although it seems a good longbow will cost you more than a good recurve (you can generally pick up a good older recurve pretty cheap), if you look around you can find a deal on one.

Good luck!

Chad