You will need help from a lawyer and professional assistance to verify that your husband has gone off the deep end. The judge will rule off on his parental rights.
If you are worried about your husband harming your children, you need to contact a lawyer immediately. The lawyer can help you arrange court dates and an investigation into your husband to determine if he truly should have no contact with your children.
Depending on the state you reside in, you may have to proove how he places the children in harm. You may also apply the information to a judge for review.
You need to contact CPS ( child protective services ) in your county and let them know your fears and ask for their assistance to keep your children safe. They will give you advice about how to document his behavour so that a court order can take effect to have him stay away from the children.