My sister has Alzheimer's and is at stage 6. She has started yelling and cursing that I am going to kill her.

She continues on with hitting, crying (with very few tears), somebody help me. I'm not kidding, she's going to kill me. Once this starts I cannot find any way for her to calm down. Often it gets triggered because she has to /or has been told she cant do something. She often says she is scared so that can be another trigger. Is there any way to get her out of this mode of behavior?