I don't really care about my brother
What did he do to make you not care anymore?
He's a complete asshole sometimes.
It sounds like he can be a real jerk, but have you thought about what he is going through at those times. It might be then that he actually needs you the most. Next time try asking him what's bothering him.
I think you are wrong about it.
You should just give it a try before you start saying that I am wrong. It is normal to care about the family around you.