IMO, it is inexcusable for parents and professional adults to ignore the damages of sibling abuse with the stupid excuse that it's just "sibling rivalry" - which is just another word for acceptable abuses by one's sibling. I went through that with my 1 yr older brother all because our pathetic parents FAILED to help him happily and respectfully accept me when I was born and he savagely punished me for many years afterwards while our ignorant parents looked on with either HUMOR or utter indifference!
I don't know what to tell you because both of you are actually VICTIMS of horrible parenting which has FAILED to promote love and respect in your family and he will respond to his parents way more than to you, who he sees as his enemy right now. My older brother decided that I was the ENEMY from day one and relentlessly abused me from then on. So long as his parents tolerates his abusive behavior and your T offers you nothing to deal with all of them, I can only suggest that you call CPS on your inexcusably NEGLIGENT parents TODAY! In my day (I'm 76 now) there was no CPS to help any kid so we just had to endure and survive. My brother and I had many savage fist fights but we survived and are now somewhat friends. I'd call CPS in a heartbeat if I were you!
good luck,
jim :)
