Just discovered that my late grandfather Chiel Jakub ROSNER(1866-1942) had a brother names Hirsch who had a son Abraham Jakub ROSNER.
This is what we know about him :Abraham Rosner, born 16.08.1885 in Zabno, Poland
Wife: Erna Rosner, née Kupferblum, born on 01.07.1887 in Ostrowitz
Abraham Rosner: Schoolboyhood/apprenticeship in Zabno/Poland; 1907 he came to Leipzig, 1909 to Düsseldorf; 1911 he founded a furniture and linen installment business in Wallstr. 47, where they lived; on January 9th, 1935 he moved to Brooklyn, USA (emigration), where he first ran a small colonial goods shop.
I found on Ancestry their entry to the USA in 1935 where Erna is Ester and no children mentioned. Abraham died in Israel in 1979 and the burial society has no record of his relatives. Ester may have died in New York in 1956(based on SSDI). A person related to the Kupferblums remembers that: "My grandfather (Gershon Kupferblum)’s aunt Ester lived in Williamsburg/Brooklyn with her husband in the 1950s. They were orthodox Jews, and ran a “wine shop.” I believe they had a son named Paul. Maybe a daughter or daughter-in-law named Rose?"
Need to find Paul ROSNER and Rose. Did not see anything at the 1940 census.