I would probably do a letter C. Others would say letter D so that the police can pick up the person who has punched the homie in the face but, I do not think that people would like that so I would rather show care to my homie so that he can get the first aid treatment that he deserves.
Getting the right treatment will also make my homie recover faster. If in case he would like to plan revenge against the person who has knocked him out will be up to him. The only thing that I can do is to help and give him advice if he asks for it.