 Through his eldest son John, he was the grandfather of Mary Christy Pratt (1923–1960), who was married to Bayard Cutting Auchincloss (1922–2001), the nephew of U.S. Representative James C. Auchincloss, in 1950.Through his daughter Phyllis, he was the grandfather of William A. Nitze of Washington, DC, the chairman of Oceana Technologies and Clearpath Technologies, who married Ann Kendall Richards, an independent art dealer.Through his son Edwin, he was the grandfather of singer-songwriter Andy Pratt (b.