How do we go about assuming copyright to my father in laws music since his death and no will was left.

My father in law deceased in 2011 as an indigent and there was no will or executor to his estate being that he had nothing and was living in a shelter. Recently it has come to light that he had publish and copyrighted a large amount of music and poetry. My husband has two half brothers who were placed up for adoption at birth. The oldest brother is attempting to assume the legal rights to the music and produce it under his name. First question does an adopted child have any rights to the estate? How does my husband go about being named executor of his dad's estate? And how do we protect or assume the copyrights?