My mother tried to operate machinery that can hurt her and when we when we try to get her to stop, she becomes nasty to us. What can we get her to stop?

My mother 87, operates machinery that can hurt her. Are we, her caregivers libel if she does, we tell her not to do these activities. She is almost blind, she is on Parkinson's and heart medicine. She has poor reflexes. She refuses to stop these activities, and becomes downright nasty to us when we try to curtail her activities