zen , i don't understand your borther's behavior towards you. no loved one deserves to be treated that way-meaning how he treated you. if it were me i'd return to school and strive to make a life for myself in spite of his absence.
i did it, i'm bipolar with a very dysfunctional family, and in order to get/stay healthy myself i distanced myself from those of my family who hurt me. today i have a huge batch of friends who love me for who i am. they live all over the US. they have remained my friends even when i've moved away from them. my familly-siblings-are back in the picture but i always protect myself from them. when i do visit them if need be i just get in the car and leave-i live over 8 hours from them so it's a long ride home but definitely worth it.
this is what my T told me a long time ago....how do you stay healthy in an unhealthy relationship (family)?
the answer-distance
perhaps one day your brother will realize what he has missed out on...a loving sister. perhaps not, but in the meantime you are forging ahead with a healthy life for yourself.