My sister has two boys and was never married to the father. He moved about 4 hours away, but still lives in the state of Florida. He has not spoken to the boys in the last month and she is not sure if he ever will contact them since moving. She is considering moving to New York in the future and wants to know how long she would have to wait if she does not hear from him to use the abandonment law. I told her I thought she would have to get his permission and I don't think the abandonment law would work. Please help.

What abandonment law? Why do you think that would apply? The only thing that would prevent her moving is if there is a court ordered visitation schedule in place and her moving would prevent that schedule from being exercised.

If there isn't such a court order in place she is free to move whenever she wants.