Frigidaire oven smells smoky and turned itself on to bake. Safe to use cook top?
I would say it is safe to use both the induction rings and the oven provided your in-law is in the kitchen.  I would not use any timer function on the oven.

The main risk is the cooker starting a fire.  If your in-law is in the kitchen, she will probably smell burning insulation, and be able to turn the power off, before an actual fire breaks out.

I would continue to turn the breaker power off when the cooker is not in use, particularly when she is out or asleep.