Can you be the victim and the perpetrator of the same crime?

Ordinarily, no - they will either determine he's the victim and not charge him or that he's the aggressor and file charges. It may have happened that your son's paperwork went to the juvenile court and he got charged, not realizing the other guy was charged in adult court, listing your son as a victim. Discuss this with your son's attorney. The DA will have to make a choice to either file against one or neither if they are counting on getting a victim's testimony. If they charge both, each could plead the Fifth Amendment and the DA wouldn't have any evidence. The other reason may be that each one - your son and the adult - are being charged with a fighting in public statute. There, it doesn't necessarily matter who the victim/aggressor was, just that they engaged in a fight in a public place.