RE: Left eyed, and right handed????
For starting out, get him a bow he can shoot either way (like a little recurve that can be shot RH or LH) and see what he naturally does. At that age, his eye dominence could change and it is often hard to be really sure anyway. Just let him progress naturally and don't force him one way or the other.
For those of you already shooting you opposite eye (like me -- I shoot RH and am left eyed), if you do not have a physical problem aiming with the off eye (like can't close the other eye, etc) there is no need to switch.
I am a big proponent of shooting which ever way is more comfortable. There is no compelling reason to really switch just to shoot the dominent eye. There are several top coach who believe this as well -- so the comment about any good coach advocating switching is false.
I shot 300-59X last night right handed, but I am left eye dominent. That one that missed the X had nothing to do with my eye. I have tried to shoot LH (just for trying) and it is very akward for me. I can't see how switching could possibly help my shooting.