"...one old man" was Alexander Botkin Huston (1829-1915),
the author's father.
The case that he argued before the
Supreme Court of the United States
was Robb v. Vos, 155 U.S. 13 (1894) in which he appeared for August Vos,
the appellee.
The opinion of the court, delivered by
Associate Justice George Shiras, Jr.,
was for Vos.
"...his father's..." refers to
Paul Huston
(1767-1844).