Document absolutely EVERYTHING, even better if you can get her to admit making false allegations on video or just audio. Daddy dearest is going to have fun arguing with a restraining/protective order from a judge... In the meantime DO NOT, under any circumstances EVER leave your kids unsupervised by you or your partner if she's around or it's possible she might show up. She sounds like the sort who would try to 'clean the vaccine poison out of them' by getting them to drink bleach or whatever those gibbering idiots believe 'fixes' it this week.

This only reflects badly on that nutcase, not on you. Does she want the kids to get polio, smallpox, Hep B, RSV, diphtheria, tetanus, whooping cough and/or Rubella, all of which are easily preventable?