DSW's tree shows Cilly and Alfred as the parents of Walter.

Alfred Horn and Caecilie Horn geb. Staub are among others who are listed in the Breslau synagogue community address list (ca 1930) at Kirschallee 36.

Alfred and Caecilie Horn geb. Staub are listed in the 1939 census of Breslau at Kirschallee 36, along with, among others, Walter Horn born 29.12.1923 and Caecilie's 15-year old nephew, Rudolph Staub whose parents are listed at another address in Breslau. I assume that Rudolph was having a sleepover with his cousin.

Alfred is listed as murdered by the Nazi regime in German Federal records.