Barend Duis was a son of Jacob Duis and Frederika Sajet. He was previously married to Sara Canes in 1897 in Amsterdam. They divorced in 1906. They had a child.
Stadsarchief Amsterdam, archiefkaart Barend Duis
In July 1941, an obituary was placed in Het Joodsche Weekblad for Barend Duis.
Het Joodsche Weekblad, 18 July 1941, 11