I really think we are dealing with some attention starved teenager here, you're a cop, is it really worth wasting your time off duty on a forum arguing with some silly kid? If it is attention he is seeking, we are giving it to him in droves.
I suggest just skipping over his posts. I know the current subject at hand is a pretty personal one, and he is making personal attacks on you, but I don't think anyone around here is really taking what he says seriously. The fact that he is making so many personal attacks is all the more reason to just ignore his posts anyway. It is getting to the point where we can't even have a discussion without it being deluted by his constant infantile remarks.
Just some thoughts.