The symptoms you describe above do not sound consistent with a stroke. Typically, a stroke would involve weakness or numbness on just one half of the body, often accompanied by
visual changes or speech disturbance. If symptoms such as these last longer than 24 hours, and were caused by a stroke, you would expect to see signs of a stroke on an MRI scan.
That said, if you suspect your sister is ever having a stroke - sudden one sided weakness, numbness, visual trouble, speech trouble - you should always call 911 immediately. There is a medication called TPA that can help reverse a stroke, but only if given within a few hours of the stroke onset. In addition, the sooner it is given, the better. Therefore, please call 911 right away if you ever suspect a stroke.
Good luck, and all my best wishes!