Couldn't hurt if Ambian does not interfere with any other RX's he is taking.
Strokes are brain bleeds which cause damage so I don't see how it can hurt to try.
Strokes are caused by a disruption to the flow of blood to the brain. Such as when plaque breaks off from an arterial wall and travels into the brain where the vessels are too thin to allow the passage of the plaque particle thus starving the cells downstream of blood and oxygen.
But I agree with the second half of your statement; can't hurt to try.