I am so sorry that you are having to deal w/this. Your mother needs professional help. Is she a danger to herself or others?

All you can do is block and delete her messages. I wish that I had an answer for you on how to deal w/her.

Sit quietly, the answers will reveal themselves when you least expect them to.
The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.