An examination of the skull cannot possibly tell you he was hit in the head and partially blocked the blow. Then turned to run and the guy he was racing connected with a side of the head hit. Then he was on he ground and the attacker hit a third fatal blow.
It could have been two or three against one in that instant. he may have been close to a comrade who was also fighting and his violent swing at an attacker connected with his friend beside him.
This is the weakness archaeology always has to guard against... conclusions and narratives not supported by evidence.
But interesting artifact.
This is where experimental archaeology could help. If they had access to some guys well trained in contemporary fighting techniques (assuming we know what they were or could approximate them), you could have them fight various scenarios to see which would be more likely to have caused the wounds.
But "more likely" is about the best you could get.
BTW, one of the more interesting observations from medieval cemeteries is the rate of homicide. I read a long time ago that Merovingian era cemeteries in France showed from peri-mortem bone cuts that the leading cause of death for males 15-30 was homicide.