My Brother's Autism Diagnosis and My Frustration with My Parents

So recently my brother got "diagnosed" with autism. And the reason that I put those quotes is that a doctor hasn't diagnosed him yet. A couple of days ago at his school, he said something along the lines of: I can't do this anymore, or I don't want to live. And the authorities and someone was called to the school to check him out and within the first couple minutes they said he has autism. The 3 doctors he has never said or took note that he has autism, maybe they just didn't think he had it. I have known for YEARS that he was on the spectrum my parents just refused to believe me. But he is getting reevaluated and is doing online school now. Which he does awful with he is just on his phone, that he isn't supposed to have, all day. I kind feel mad that they never believed me. He is a very typically autistic boy, he is white, and young. I have never liked my brother, in fact I have always hated him. Which sucks but he is a HUGE asshole. He only thinks about himself, He doesn't have empathy or sympathy, Has a huge temple, And is emotionally, physically, and mentally immature/ delayed. Like REALLY delayed. He acts like a whiney 4 year old when he is 13. Now he is at home all the time and is constantly in trouble, which is the norm. I can't wait the graduate high school and not ser him for a long time....