My 75 yr.-old mother has had multiple tias. could this be causing her to be abnormally hot all of the time?

Probably not. : This is not a common symptom of stroke/TIA. There are some other medical problems that can cause increased basal body temperature or sensation of increased body temperature. Her physician should be able to diagnose these with some simple lab tests. Common things being common, it is important to make sure she is not having fever or simply making herself too warm with clothes or a heater.