Listen carefully, my friend. You must protect those children. I want you to insist on a parenting evaluation - YOU PICK THAT EVALUATOR - with a psychological evaluation as part of it. This is gonna cost you thousands of dollars, but it's the only thing that's gonna protect those kids.
Start protecting yourself and your kids. You have to keep reminding yourself that she is no longer your friend.
"The dark does not destroy the light; it defines it." - Brene Brown