What can my friend and his girlfriend do after they got arrested on a traffic warrant?

He was searched by the arresting officer and he didn’t find anything. When the transportation officer searched him he found a small bag of narcotics. The arresting officer acted like the little bag wasn't a big deal and said it didn't look like much of nothing, but the transportation officer made sure he got the charge. When he was released and given his property, they had given him some of her stuff that she was arrested with. He was put on a breathalyzer machine which doesn’t make any sense and a house arrest. I guess what I'm getting at is I feel like the whole situation wasn't handled correctly.