How can i help a friend on meth?

You can't: Only he can help himself, but there are things you can do that first of all help yourself (and other friends/family), and may ultimately help him. Family members often "enable" drinking, allowing the person to get away with behaviors that are unacceptable. Alanon and Nar-anon are programs for family/friends of those with addiction and can help you understand what you can, and can't do. Good luck.