He was arrested because he had a warrant out on him for child support last year from where he lost his job but since then he has paid all the past due amount and has paid the amount required of him every month.
If your brother is in jail right now then he is either waiting to be arraigned or that has taken place and bail has been set. My advice is for you to obtain legal council, go to where your brother is and figure out the situation and what you need to do.