Understand that someone in your situation is considered a "third party," and cannot file for custody of the children. This is because no statutory language allows a third party in NJ to file for custody of a child. The Court can use some equitable doctrine to perhaps justify it if the children had lived with the third party, but they had not in this case, so this does not apply.
One's best option is to perhaps file a complaint with the NJ DCF (child protective services). DCF has the statutory right to stand for custody for children if a child is being abused. If DCF feels the issue is serious enough, they can mandate that the parents take parenting classes, or else risk having their custody taken away temporarily/permanently (ironically in such a case, DCF would then generally attempt place the children with extended family such as yourselves).
However for DCF to threaten custody action, the abuse/neglect has to be serious. The emotional abuse has to be serious.
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