I just want to add what that email stinks of.
Manipulation.
Demeaning.
Entitlement.
That email reeked of those things.
In the predator vs prey world, she's after you.
And she wants to take you down, as low as she can, while building herself up in whatever twisted image she has of herself as a "wonderful" grandmother and mother.
She's made you her mark.
I'd avoid her like the plague, and I'd pass along that caution to my kids.
She has no right to them, although I'm sure she has already googled grandparent's rights, as some states will dole them out.
But without honest love, she will get nowhere, not with you, not with them.