You could go to your brother and ask him what possessed him and maybe you could work out some kind of plan with his help to gradually introduce the thing. He is 19 after all and legal age to function without his mother.
I had such a bike when I was 19 and also had a 400 HP car to drive that was my dad's. I had always been a science nerd but became intensely cool with muscle power like that. I was one wild MF'r but survived. Survived a lot of drugs as well.
So far.