See that's the problem. His surname was from a man who was not his father, only given to "legitimize " him. That man died 2 weeks before my father was born. He was my grandmothers husband but had been terminally ill and bedridden for over a year. My grandmother said the real father was the brother of a neighbor, and lived in another state. No names.
And...my father has no living males who share his DNA. He has only sisters, no brothers, and I'm his only child. I wish I could get him to take a DNA test but he won't do it. He's convinced the government is using that as a front to keep a national DNA database. Yes, I'm serious. <sigh>