Sonkie, no wonder you're fed up, you're struggling in very difficult circumstances at the moment, you've got enough on your plate with your brother and having to put up with so much at home, would be enough to drive the most patient & saintly of us to drink, let alone muffins.
Don't beat yourself up hon, you are doing an AMAZING job, you really are and taking so much sh*t, TBH from your OH.
Stay strong & try to keep a focus on your diet, it's something in your life that you can control at the moment.
I don't know what to say about OH (that's printable) but I think it's all going to come to a head soon, and you need to have a long hard think about where you want to go with it all. And then try and talk to him about it, I don't suppose for a moment he'll listen, but if you can, you need to try and let him know how you're feeling and what he's doing to you and really whether you want to stay in this relationship or not. Only you can decide the answer to that.
Take care hun, lots & lots of love
xxxx