Sure he had a head injury ... he bumped his head on a vehicle when he was getting out of it.  I think everyone in the world has that "head injury".
 
"An official told ABC News that the soldier has suffered a mild traumatic brain injury (TBI) in the past, either from hitting his head on the hatch of a vehicle or in a car accident. He went through the advanced TBI treatment at Fort Lewis and was deemed to be fine."
 
http://abcnews.go.com/International...ssacre-brain-injury-marital/story?id=15900289
			
			"An official told ABC News that the soldier has suffered a mild traumatic brain injury (TBI) in the past, either from hitting his head on the hatch of a vehicle or in a car accident. He went through the advanced TBI treatment at Fort Lewis and was deemed to be fine."
http://abcnews.go.com/International...ssacre-brain-injury-marital/story?id=15900289