Spreading is not possible, What might be possible is that small clots are still being showered into the brain from another location. You will need to ask very specifically what they mean by spreading. They are trying to bamboozle you with words that you don't understand. So call them on it and demand answers, I know they will say they can't tell for sure what is happening, but ask them why they don't know. This is the only way survivors will ever get knowledgeable answers.
Dean
The term "stroke" is in itself meaningless in understanding what has happened medically.
Basically there are two kinds.
(a) strokes caused bleeds
(b) strokes caused by clots
If the bleed continues and blood keeps oozing into the structure the stroke "could spread". Blood vessels are cauterized with hot coils or anti-coagulants are administered to facilitate clotting.
If a stroke is caused by a clot, provided there are no more clots, the damage will stabilize and not "spread".
I se no reason whatsoever to assume the physicians that treated your aunt are "covering anything up."