i would pick up the marble so that no one else falls over.....

as far as i know there is nothing you can do for a stroke victim....you could give asprin to him to help the blood flow back to the brain....but weather this will really have any effect, i do not know....
but i wouldn't really mess around with that for too long....the sooner they get to a hospital the greater their chances of fully recovering without serious braindamage.