My brother Jonathan, who is 16, was in a four wheeler accident on the 4th of July and hit his head. He was wearing a helmet, but gave himself a concussion. A few hours later, he couldn't remember anyone or anything except his girlfriend and brother Joel (who he was with right after the accident). Cat-scans show no signs of significant damage, but he still can't remember anything. Doctors say the brain needs time to heal, but they have no idea when or if his memory will return.