wooit.....
Hey ShredSweeper, I'm sorry to hear on ur situation.
Well, I do see a lot of situations like this before. Personally, I would think u should move out to ur grandparents' place since they dote on you. Confide with ur grandparents. Running away from home doesnt solve the problem, instead they would give in more reasons to hate you more.
Your siblings are a load of Pea-holes. No sibling should ever do that to their own bros/sis. Are you the oldest or the youngest. The best thing is to show your stand on this. "Rebel" against them and instill fear towards them. Never mind if ur parents call u " the black horse" in ur family.
Another thing is, be successful. No matter how far u study or wat, still u can be successful. Show ur talent more. I see that u can play the guitar? Form a band, set ur own sights and make the band successful. In future, U will see ur family members running towards you, saying "My son/brother is a star!!!" or " U saw the guitarist from XXXXXX, he's my brother/son!!!" Tell me, that's the best trick ever to bring ur family together!!!
All the best to you!!! Good Luck!!!