I can relate so well to your life and your family situation. In a nutshell my family is fully flakes and is (was?) completely dysfunctional. I am the black sheep, my family cares nothing about what happens to me and has long since even asked or offered help when I needed it. i left them over a decade ago and have not looked back since. I understand completely and being older as I am I just hope you take my words to heart as I've been where you are.

living your life and finding success is your best revenge on them. You can find happiness and fulfillment in your life, even create a new family in the sense of finding people worth of having in your life that actually are truly friends, supportive and loving. Family, beyond genes is nothing. Sure i n an ideal situation, you end up in a family that is loving and caring but you didn't get to choose them and if you end up with dysfunctional jerks as you and I have, you have to just let go of the idea that just because she's your sister she should act like one or your dad should be one.. Just find the things you need from other people and its even better than family if you ask me

hang in there. I know its hard some days to hang on and keep going but there are better days ahead.

*hugs*
~S4