Genetics plays most of the role in height. You can only adversely affect it with either too much working out too early, or not supporting it with nutrition. His body will have a growth period, and if he's supplied with all the proper nutrients to promote that growth, he'll grow. If he isn't, he won't.
My father is 6'3", my mother is 4'11", I'm 5'3". Most of my features come from my father, with a select few from my mother. I spent my youth playing 4 leagues of soccer, paintball, and otherwise running and biking all the time. I didn't eat right at all (father wasn't in the picture, and my mother's idea of feeding me was apples and pop tarts). Needless to say, I didn't have the right kinds of foods. Doctor said for my build, I should be at least 5'8", but I likely stunted my growth with being too active and not eating right. Oh well.
Keep him well fed with good nutritious balance and you'll be good.