David Pach was a son of Philip Pach and Roosje Koopman. He was the 2nd spouse of Esther Schelvis (marriage Amsterdam 7 Juni 1933), who previously was married to his first cousin Levie Pach, a son of David Pach and Golde van Duijm but who has died in 1930. David and Esther had no children, however the children from Esther and his cousin stayed in his family.
City Archive of Amsterdam, archive card of David Pach.