Reading back to the original post, something struck me as odd

"we didn't so much as get a thanks from her or our son" Your SON didnt say thanks either? What does that say about him and his manners? And please dont blame her for that, he is a grown man...
I think you should let it go. If he wants to stop fine, if not then fine.. Just drop it before you end up gettign really hurt by your son...