Could pouring water on your head during a stroke attack stop the attack?

Sure wish it could: Stroke is like a heart attack, but it affects brain. It is indeed a medical emergency, but early rapid treatment with tpa (alteplase) or catheter balloon or extraction can often reverse and stop the potential damage. So, if you or relations have stroke-like issues have this handled at the nearest hospital.

No: It will not. Seeking immediate care in the nearest er is the best option.