I read your query and I understand your concern.
From what you describe the cause for stroke apart from old age is also the presence of
high blood pressure and
diabetes which damage the walls of the blood vessel. I understood she took treatment both for them as well as
aspirin, so the correct measures to prevent it had been taken, but unfortunately they just lower the risk do not eliminate the possibility of it happening completely.
If the interruption of blood flow is not removed within a few hours the damage is done, some brain cells are irreversibly dead, so some degree of
disability will probably remain if she's paralytic.
During the first few days apart from the
paralysis itself there is also the risk of complications such as swelling of the damaged area or bleeding inside it, complications which are life-threatening due to the increased pressure inside the head. Also due to the paralysis due to the immobility there is an increased risk of complications like infections or
deep vein thrombosis.
If she overcomes this initial life-threatening stage improvement is expected thanks to compensation of the uninjured brain for the damaged area. The degree of this improvement depends on different factors such as how big was the lesion in first place,
physical therapy, age and general condition, it is not an exact equation, but usually there is improvement during the first 3-6 months, so it's a long process which takes patience.
I hope to have been of help.