Quoting Princess Celestia:" Well, I'm not sure of the legalities of it, but my ex-stepfather never paid a dime on my sister. Exact ... [snip!] ... his rights. She won. So, it's definitely possible. Is there any way she can prove that he's violent or ill-fit as a parent?"
I'm glad there's hope for her, she's pretty distraught. She has the restraining order, which was for her & the daughter, over domestic violence. How he's been does follow her states definition of abandonment, which is to have made little to no contact in a year or more, have paid nothing to support the child in a year or more and disinterest of the child.