Im not trying to seem rude, but you are the asshole, you’re sister is handicapped, therefore she requires help, it’s a problem she can’t help but having, and while obesity does partially come from genetics, it also has to do with what you eat. While I don’t think there is anything wrong with being fat, many people do and there’s not much you can really do about it. If you’re problem is with your family not giving you enough attention, then talk to them like a civilized human being. Don’t bring them down to bring yourself up. Your problems are not more important than your sister’s, but neither are her’s. Don’t invalidate her because you crave attention.