I am writing a play in which an unmarried mother dies in childbirth due to complications caused by cocaine use. Before she goes in for the fatal delivery (the child lives), she asks her sister to promise to raise the child because she doesn't want her cocaine dealing boyfriend and his mother to get custody. Because of the death the biological father dramatically reforms. His mother petitions the court for custody. Even though he feels the sister would do a better job of raising the child, how would the court be likely to rule? I don't mean for this to appear frivolous because I think the parental issues presented in the play are important for a large audience, and I want to get the legal issues right.