One does NOT need a license to observe another hunter, but one does need a license if they participate in the hunt. There can be some gray area though in what constitutes participating.
Consider the case of a cameraman, who does not need a license and may or may not have one accordingly, that says to the licensed hunter..."Here comes a buck." Does that constitute "participating"? I have heard conversation that one CO may not interpret this as participating, but another possibly might.
If you are just chaperoning your son I can't see where that would be any type of a violation.