Hit and run misdemenor?

My boyfriend was involved in a hit and run. He did not cause the accident. The woman who hit him did but he didnt care about property damage to his car. So hhe waved her on and they both Left but she called the cops and said he left. And it was his fault. So the cop said what she said and what he said happened was diffrent. He just got a court date, and its his first offence. Does he need to get an attorney? What do you think his probable punishment is?