Omy , you do have a problem. Since they were not marrie before she became pregnant he is not the presumed legal father, and now that he has passed, unless a DNA test was done before death,it will difficult to petition a court to declare him the legal father, though it is possible with mitochrondrial DNA tests.
Was he declared the legal father before death? what was his legalrelationship with the child before death?
Once I know more, I might can offer some suggestions

