First of all, hugs - I'm so sorry to hear you're struggling with your relationship with your brother
Family is such a goofy thing. We attach all of these societal expectations to our familial relationships (like, what a brother *should* be like), but at the end of the day, our family members are just other people - and like everyone else in the world, some of them are good or bad. Just because we're tied by genetics doesn't mean that the relationships we have with our family members are inherently positive.
I mean, if you had a friend who was doing all of the things you describe above, would you even hesitate to cut ties? Why would it be okay to continue to allow another person to treat you this way, just because he's a family member?