We tried getting through to my brother

My little brother is 17 and he's been thru a lot. We have different moms and his was super abusive. She used to light cigarettes out on him and would beat him and let people sexually abuse him in front of her as punishment. My brother started seeing this girl when he was 15. I was 23 at the time and never hated a 16 year old more than her. She was extremely abusive towards him and would tell him he was worthless and try to convince him to self harm and kill himself. Then this bitch got him booked on drugs. So he was out running the a streets doing drugs with this abusive pos. She was hitting him and stabbed him AR one point. He then got her pregnant... They have a daughter now.. His girlfriend at the moment is in jail and.looking at 20/Years in prison for something very disgusting. My brother has been arrested and in mental hospital after mental hospital for trying to kill himself. Their baby is getting adopted out because they got her taken away and neither are fit parents at all. So rn the court is trying to take away my brothers adulthood when he turns 18. Basically they don't think he ia capable of making adult decisions. So even when he is 18 he will need a legal guardian who is in charge of his money, making sure he takes his meds, making important decisions, he will basically still be treated like a minor. We tried holding an intervention today. I told him I love him but he needs help and this is a dark road he's going down. He's already lost his daughter and he needs to get clean and he told me I had a good mom so I have no idea what he's been thru. My mom said "You can't blame your mother for how you turned out. She had NOTHING to do with that. You chose to let abuse get to you like this". So my brother threw something at her and started screaming " YOU DON'T KNOW WHAT IVE WENT THROUGH!!! NONE OF YOU DO! NONE OF YOU WERE THERE!!! I HATE ALL OF YOU!!!" I got up and hugged him and he's bawling whispering to me "I hate you. I hate all of you". But I still held him. I don't think we've gotten through to him... If he doesn't change something he will need a guardian. That will most likely be me and I'm not upset about it, I just really wanted to try to convince him to turn his life around before it came to that so he can be a responsible respectable adult.

Edit: It would most likely be a while before the court considered giving him.his independence back. I talking years of not just me but his case worker tracking his progress.