Sopfia & Siegfried (later Sidney) Katz were born in 1907 and 1909 respectively in Dornawatra, Austro-Hungarian Empire (now Romania), daughter & son of Moses Hersch Katz & Amalia (Breyer) Katz.
The family moved about 1916 to Gmund, Austria, and later (Siegfried at least) to Vienna. Siegfried married Hilde Fränkel about 1936 and in 1937 they had a baby girl Lydia. In 1938 Siegfried, Hilde & Lydia escaped from nazi-occupied Austria to go to Trinidad and later Brookline, Massachusetts.
But what happened to Sopfia Katz, Siegfried's older sister? Did she die young? Did she marry and so we cannot trace her because we do not know her married name?