His parents' death certificates show that he lived in Dresden in 1898-1900. Both certificates list their nine surviving children in order of age and place Otto last, meaning he was born no earlier than 1876. All of their children from Martha (1860) to Willy (1875) were born in Kattowitz where Louis had his business, so it is likely that Otto would have been born there.

The 1939 census of Berlin lists an Otto Adolf Borinski, born 05.03.1883 in Kattowitz. His second given name, Adolf, is consistent with Otto's paternal grandfather of the same name having died in 1878. Bertha would have been aged 45-46 years at the time of his birth, which is just about credible.

No obvious family members are listed at his address in the 1939 census.

Yad Vashem has two records for this person, identified by his name, date and place of birth and residence in Berlin; One details his deportation to Riga on 14.12.1942, the other simply states that he was deported to Auschwitz concentration camp. Of these, Riga seems the more likely destination as details of the transport are recorded.