My Grandma is getting worse, and tonight is by far the hardest. She keeps getting mad because she thinks that her Mom and Grandma (Died 45 and 58 years ago) abandoned her to go back home to Elgin, that her Dad (Died 63 years ago) is sick in the hospital, and is yelling at me to get her husband (My Grandpa died 5 years ago) on the phone so she can find out what's going on. Then yelling at my Dad for being out all night. She is screaming, yelling, crying, and had physically hit ant bit me out of fright. She's finally worn herself out, but stuff like this has been happening more and more often. Is there a way I can calm her down the next time she gets like this? So far this has been going on for around 11 hours.
If she becomes agitated and physically abusive, I think calling 911 and having her taken to the hospital is the compassionate thing to do.
I can't imagine having a loved one in that much psychic pain and not taking action to stop it. To be clear, I'm not faulting you for not doing that this time, I think this is uncharted territory for most of us the first time it happens. But just know that calling 911 is an acceptable response.
There are also techniques for calming someone with dementia found on You Tube. You can use key works like Teepa Snow calming dementia patient. She has some great demonstrations, however, for the degree of anxiety that your mom seems to have, I'd definitely have her evaluated by a doctor.