Get him evaluated.
Where was the hematoma, intracraneally or superficially? Superficial or subcutaneous hematomas do not cause problems, they disappear within few weeks or months.
I think that symptoms now have nothing to do with what happened in 2009 unless he had intracraneally bleeding that grew slowly (?) headache
may well be signs of intracraneally pressure or more commonly something less serious.