There is just too much hurt..:( my family is broken, please help me?

I'm 17. My brother is 19 and he recently got caught by my parents smoking weed in our house. He went to University of Colorado Boulder for his freshmen year of college and he did very poorly with his grades. I already knew before my parents caught him that he was smoking weed. My parents found a bunch of weed and alcohol in his bedroom and my dad kicked him out of the house for the night and then they let him come home but then today my dad found another pipe in my brothers bedroom and he kicked him out again. My brother has been suffering from depression because of a really bad break up with his ex girlfriend. I feel like im in the middle of all of this and i dont know what to do anymore. I want to be there for my brother cause im really all he has right now..he is staying at my aunts house right now. My parents are hurting, im hurting, and so is my brother. I dont think him living at my house will help anyone or anything...but then again i dont think that my parents paying for him to have an apartment by himself where he can smoke weed all day would be good either. I also feel guilty because i occasionally smoke weed also :/ i dont know what to do..nothing feels like its gonna be okay. any advice please?