Dear Florence, to my knowlege, honestly, I don't know of anything more you can do. Realistically, she isn't probably going to change. Ignore it; compartmentalize it; detach.
If you don't expect any different --you won't be too disappointed.(LOL).
My impression is that she does have some other redeeming qualities, and, I'll bet the kids like the idea of having a grandma. If this is true--I implore you to reconsider something so drastic as to cut her out of your life. Sometimes, when we are annoyed by the "bad" parts, we forget the "good" parts.
I buried my 92yr. old mother 41/2 m o. ago. Florence, she was not an easy woman--NOT...AN...EASY...WOMAN........!! I would give anything I own to have just one more hour to talk to her.
Perhaps this is the down side of being the one who lives the closest..
dandylion