I'm starting to resent my brother

I used to struggle with anorexia, I would frequently fast for 7 days at a time and more recently I've regained some of my weight because I attempted recovery and I'm spiraling into binge eating because of stress. My brother was the only person I opened up to about this. He has been going to the gym for like 3 years and ALL the time he talks about how perfect his body is he'll just walk into the room and take his shirt off and go "Look, I have the perfect proportions, I have perfect body ratio, OMG my waist is 28 inches and my chest is 40" at first I thought he just forgot about my own issues so I tried to brush it off but even my mum complains about him being so obsessive and it's really starting to eat into me and I couldn't possibly relapse at this stage of my A levels but I can tell I have been and I feel so weak and angry at him. He always makes jokes about how he's so anorexic and "Oh no if I eat that, I'll have to be sick later ahahaha". I try to make it obvious that it annoys me but I always end up storming out and crying myself to sleep. Iknow I should just talk to him about it but I don't know how.

U need to ask him to stop, when you’re one on one with him, tell him ‘hey do you mind not making anorexia jokes they make me rlly upset’, he should stop after that, if he doesn’t then he’s a terrible person