Hello 
Thank you for your question.
The description of symptoms in your mother along with her medical background is suggestive of a condition called 
Transient Ischemic Attack.(TIA)
Transient Ischemic Attack is a form of stroke which completely resolves within minutes to hours, typically in less than 24 hours.
Symptoms include weakness or numbness of limbs, slurring of speech, transient blindness or 
dizziness or loss of coordination.
Multiple TIAs could imply increased risk of a stroke in the next few months.
The risk factors for a TIA are increasing age , prevous history of a TIA, 
Hypertension, Diabetes , 
High Cholesterol etc.
As you have already been to the hospital, I think you would have already a got a basic  blood workup along with CT Brain and a Carotid 
Ultrasound.
Your physician will  prescribe antiplatelet drugs such as 
Clopidogrel, apart from your regular medication for hypertension and 
diabetes Mellitus. You will also need Lifestyle modification  such as avoidance of smoking.
It would be useful if you had mentioned more details such as the onset of the episode , which limb was involved etc. There could also be other reasons for this presentation. I feel considering her age and medical background ,TIA is a possibility.
I hope you have found this information helpful.
Regards 
Dr Alex