A "closed head injury" (no open wounds) resulting in any form of unconsciousness, should result in a Pilot Licence being immediately suspended.
Usually suspended for 12 months on the grounds of epilepsy occuring.
Mine was judged as a 0.1% chance of epilepsy occuring in the 12 months following the incident and thankfully I proved them wrong. I regainied my licence 10 months latter and have held Class 1 medicals since (10 years).
Hope this assists.