Hehe, if he wants to learn how to program rather than be outside, then by all means, let him! I remember when I was a 10 year old kid and wanted to learn how to "use the computer", my mom wanted me outside instead and it was a HUGE let down. To this day I wish she would've let me spend time on it because I feel that I'd have that much more experience under my belt.
You don't need math knowledge to be a good programmer! The highest math I ever had was Calculus and I'm a self taught programmer that knows Java, C, C++, .net, etc.. Hell, I had my first professional programming job at 16 when I was still taking algebra in high school. Granted, it makes it somewhat hard to do advanced 3D graphics without knowing what sin, cos, and tan are, but the basic know how for what you need to know can easily be found online.
In fact, if a kid knows a programming language and wants to make games w/ fancy 3D, he'll be that much more interested and determined to learn the math needed, plus it will seem more practical to him.
I started off programming in Visual Basic and moved up from there, although I wish I would've learned C/C++ first. If he gets used to learning Basic, the jump from that to C/C++ is VERY confusing and hard to get used to, so you might want to just start off with C since you won't have to explain classes just yet. Make sure he's got the fundamentals down pat, but you'll also have to explain to him that he won't be programming games overnight and that it'll take quite a bit of patience, practice, and experience before he gets to that point.
http://www.gamedev.net/ is an excellent site that has everything you'd need as a starting point.. math forumlas, pointers to learning languages, etc..