You've given us very little information. What do you mean "tried everything"? What have you and your mother tried?
What is your family situation? Are there other siblings, is Mom single, remarried, having problems with Dad, working? What's Dad doing? Who are his friends, what do they do together? What are his teachers like, how does the school faculty talk to him about his attendance? What is your attitude regarding the whole thing? Your mother's? If the adults in his life are giving off "I'm sick of dealing with this" then all pep talks in the world aren't going to help him much.
All this things plays a part in his behavior. So anything more you are able to give us the better able we are to help you. You don't have to tell us, but you should take these things into consideration when dealing with your brother.
Also Senya's idea about making him pay rent if he doesn't go to school and be willing to toss him out is NOT a good idea. The last thing a child needs at that age is to feel unloved. It will only make it worse, and cause more heart ache for you, your Mom and your brother. Never mind the fact it's illegal to toss a minor out into the streets.
Remember, your brother's brain is not finished growing and won't be until the age of 22-25. Yes, seriously. He's not even a legal adult, so treating him as though he is an independent adult would be disastrous.
Other than this idiotic piece of "advice" you've gotten some good general advice.
I'm taking a motivation class this semester at SJSU, it's about how to motivate children and adolescents in school. Maybe I'll learn something that might be more helpful to you. If so I'll pass it on, feel free to email me ____@____.com so I'll have your contact info at my fingertips (I'll likely lose track of this post later).