Which one of Alexander Hamilton's family members was also killed in a duel?

Answer: His eldest son, Philip Hamilton

History - On July 11, 1804, Alexander Hamilton was shot and mortally wounded by Vice President Aaron Burr in one of the most famous duels in American history. Though this was Hamilton’s first—and last—duel, he was certainly no stranger to the practice. One of the most divisive and combative figures of his age, he had already been challenged to nearly a dozen duels during his life, but each time he had managed to avoid violence. His eldest son Philip, however, was not so lucky. In 1801, after witnessing a speech denouncing his father, 19-year-old Philip confronted New York lawyer George Eacker and demanded a retraction. When Eacker refused, a duel was set for November 20 in Weehawken, New Jersey. Eacker escaped unscathed, but Philip died an agonizing death the following day. The loss devastated the Hamilton family, and many historians believe it led to Hamilton’s own reluctance to fire directly at Aaron Burr during their legendary duel just three years later. Whatever his intentions, Hamilton missed his opponent but was promptly shot in the stomach; he died the next afternoon.