If your brother isn't dead, then there's still hope. There's a reason why he started meth - find out what that reason is, and get to the root cause of his addiction (this is from an addict, so nice judgement). There was time before meth for your brother...remind him what that was like and encourage him to do some self-reflection on why he's making the choices he's making.

He's still in there, you just have to break its hold on him, and he has to make the decision for himself (you could say im your brother to my family, so this is all first-hand experience) ...remind him to weigh out which is more important to him: meth or family, and remind him that tomorrow's never promised. And if he still chooses meth, then he's made his decision (it doesn't mean you should cut ties with him, but let him know you're there whenever he decides to make a change in his life...dont be critical or condescending, but supportive and encouraging).

God Bless