Julie
I'm sorry he's acting so insensitive. Is he still on his pain medication? That might have something to do with it. I'm not trying to make excuses for him - and nothing excuses just being plain mean to someone else - but I know you were concerned because he wasn't bouncing back after his surgery.
My only advice to you is to just keep doing your thing, ignore him as much as you can and maybe he'll get tired of talking to the wall.
People can just be so hurtful sometimes......makes me enjoy my cats more and more!!
I'm praying for you!