What is the succession of ownership in Texas when all of the immediate family die except for the spouse of one of the sons?

I am involved in selling a house where the deed is in the names of a couple deceased. A friend of mine is selling the house. She is widowed by the son of the couple. There was one other son. Father, Mother and two sons and the spouse of the older son. All have died except my friend (the spouse). The younger brother died 7 months after the older brother. He was single and without heir. My friend is using a small estate affadavit of heirship to transfer title. My question is this: How does the younger son's death occurring after that of the older brother (my friend's late husband) effect her degree of ownership and her ability to complete this sale? I am looking for a general answer based on this information. We are waiting for the title companies's examiner to approve the closing.