I’m sorry to hear that. It sounds like a difficult situation to deal with. If your daughter is intentionally lying to your grandchildren to cause fear or harm, this could be considered emotional abuse or psychological manipulation.
It may be helpful to try and address the situation directly with your daughter and express your concerns about how her behavior is impacting you and your relationship with your grandchildren. You could also consider seeking the advice of a family counselor or therapist who can provide support and guidance on how to approach the situation.
If the situation becomes more serious or you believe that your grandchildren are in danger, it may be necessary to involve the authorities or seek legal advice to protect their well-being.