He's not responsible for having MI but he is responsible for taking care of himself and making sure that he doesn't treat others poorly and act abusively toward them.

The whole "abandonment" thing does get a bad rap at times. Yes, it sucks to be abandoned by others, and I hate it when people lay on a guilt trip when you remove someone from your life, however we all have our limits. Why should someone feel guilty for disconnecting from someone who acts abusively?

I think you should have a heart to heart with your brother. Tell him that his behavior is unacceptable and you won't tolerate it. When he does treat you like crap, walk away or ask him to leave (if its your home). Sooner or later he will realize that if he wants you in his life, he can't treat you that way. This way you're giving him every opportunity in the world to stay in your life, with the ultimate decision being his. Also, tell him that you're concerned that his medications aren't working. Its not just about taking meds, its about taking the right meds. Medications can poop out over time. Consistent med monitoring is a must along with the client being honest with their doctor.

I think its great that you want to support your brother, but remember that you must always put yourself first. If he is taking you down, its time to jump ship. Its noble to want to help someone else, but we can't sacrifice ourselves in the process.