How long has your brother been living on his own? If he lived at home with you during the last few years he probably already knows about your bedwetting. If you are not sure, ask your mom or dad. If he doesn't know, your mom or dad should tell him before you go. After all, he is your brother and you shouldn't need to keep secrets from other family members. He might tease you a little but that's part of being brothers. He would never embarrass you in public or tell any of your friends about it.