This is tragic, OP. But I have a theory Mrs Wilder has some sort of hypnosis abilities. That’d explain how she brainwashed 4 kids into thinking they are hers and your mom’s unusual behavior. Assuming this is true, calling police or any other emergency services would be pointless - they will be hypnotized just like the people in the neighborhood. I suggest pretending that you are hypnotized too and play by her rules. Meanwhile, try to find out more about Mrs Wilder’s identity. However, something tells me it’s not even her true name. Be careful, OP. Don’t trust anyone, even your mom