Take a good six months where you don't think about your brother or mother and just think about yourself. Use your money to get a good therapist, an apartment for yourself, in school (or wherever you want) and a little part-time job or something so you're busy and don't have time for your brother's drama. Leave those two characters alone for a bit to stew in their own juices and find other fish of your own to fry. Your brother isn't likely to suddenly start being lovey-dovey to you, so give up any goal of his civility until you're sure of yourself and that you're own life is on track.