Dear friend, welcome to HCM.
I feel sorry for the entire episode.
was his BP high or low to need heavy doses to control?
if it was remaining low, it is not a good sign.
also I need to read the actual scan report to answer more specifically.can you load it here?
due to the damage to the brain due to trauma, one becomes unconscious to avriable levels of coma
and for variable periods.
regaining consciousness depends on many factors. and your treating neurosurgeon will be the best person to tell you the prognosis (outcome). you can freeely discuss with him likely outcome.
I hope to have answered your query satisfactorily.
Take care and please keep me informed of his progress.
Good Luck !
May I request you to rate your experience here before you close.