Hi, thanks for using healthcare magic
There are some cough
medications that can raise blood pressure, if your mother in law used any of these, it may account for some of the elevation.
Since it is significantly above what it is normally, you may want to consider having it repeated.For the repeat measurement she should be seated for at least 5 minutes, no coffee or tea 1 hr prior to the reading, empty bladder and bowel, wait 2 hrs after a big meal.
It is important to follow up on any investigations suggested by your doctor.
Additional tests would be kidney
function tests, cholesterol
tests and screening for diabetes
I hope this helps