It's hard for him too, he most likely feels helpless, his girlfriend is attacked, he couldn't protect her, he is lost, doesn't know how to help, in his desperation he tries to make her laugh like he used to, oops, that definitely went wrong, maybe if he also went to the counselling sessions he can learn how to help. No one but a professional could know exactly how to help and even then they don't always get it right, tell him to cut himself some slack this is unfamiliar territory for you both