Funny that his response was in the form of...Well, then how did you catch me? Sigh. Once again blaming, this time your son. How about a reply like this...."I caught you because you were doing it again, you stupid sob, nothing more complicated than that." Big LOL (This time I am just kidding!)
If you did recall it, great. If not, let it go and try not to let him engage you in R convo for a while.
Just shocks the hell out of me that these MLCer feel that they can say anything to you.
Thinking of a Dr. Philism here: You teach people how to treat you. Just a thought.