If he never denied been in the states without papers he told them everything what charge can they put on him??? This is his first time going through this? How much time will he have to do if they don't deport him right away?

Something caused the sheriff or police to pick him up. What were those charges? If he was charged only as an illegal then he'll be held indefinitely until a judge determines what will happen. Without more specific information about the charges, we are barely guessing.