Parental rights of kids was terminated with 1st wife & had a child with 2nd wife. That child dies are kids from 1st wife heirs to child of 2nd wife?

My cousin who passed away did not have a will. His father terminated his rights with his children from his first wife . His father remarried and had him. His father and mother have passed away. After his fathers passing he found out his father had children with first wife. Are the fathers children from his first wife heirs to the child with second wife.