Help what does this dream mean? I'm scared?

No, this shows you're concern for him becoming a new driver though. In your subconsciousness, you secretly, perhaps even unknowingly are worried about him going to learn driving. Maybe you've related other things he's done to it and think he's going to be less than careful about it too. You're concern is common, and obviously you love your brother deep down. He's going to do great, probably have the time of his life learning to drive, and you can rest easy knowing that deep down you really care.