It may be a coping mechanization, but it's also a way of distancing youself so that you don't FEEL your feelings. You turn them aside and don't take a long look at them and figure out what they mean.
This is a trigger-thing for me.
FWH would turn aside all serious attempts to connect with humor. He would PA try to score points on you with cruel humor. He would use humor to gage how much you were paying attention when he tried to slip something by you. And he would grin-fuck you saying whatever you needed/wanted to hear in a jovial way, while thinking No Fucking Way Am I Going To Do That in his mind, so as to keep you off of his back.
One of the things that attracted us to each other was our senses of humor. One of the things that is a trigger to me is that sense of humor right now. One of the things that we are fighting to create balance for, is what, exactly is a healthy sense of humor. Because I refuse to let any of that shit go by any more.
His joking of the A is him dis-respecting your feelings and minimizing the effects of the A. As if, if it's sorta funny, then it can't be bad now, can it?
Call him on that and nip that right in the bud. Its about as funny as having him served with divorce papers during his mother & father's anniversary dinner.