^. Know that it's fabricated. Because it is.
To be honest dood, your brother doesn't give enough of a shit to care about you eating, yanno?
Baby steps though. Force yourself to munch on a little something in the room when they're around, even if they're not watching you. Even if you're on your way towards the door. Something. Just gotta push for it. It's when you stop trying to fix this stuff when you've got a problem. And when it gets a little more comfortable, kick it up a notch. Never settle into any of it until you're over it. It'll be long and trying, but don't ever stop.