Dad's Memoirs:

Father had two sisters, an older one by the name of Vally and a younger one, Toni.[1]

...

Toni married Martin Rosenthal and lived in Berlin. They had only one son Werner. The Rosenthals were very poor. He was an unsuccessful salesman of hats and somewhat of a hypochondriac. Aunt Toni worked very hard to make ends meet by taking in boarders. They were also deported but survived and spent some time in a refugee camp in Germany where aunt Toni died. Werner had not been with them. He had emigrated to Palestine before the war, and uncle Martin joined him there. Werner worked as a policeman, got married and, I believe, had a child.[2] Again, unfortunately, our correspondence ceased in the early 50's. I really don't understand why. Werner had my parents' and my address.

Notes:

1. The deportation records always show her name as Antonie, but I have left this headed as Toni.

2. Photographs (presumably from Grandmother) show Werner with a wife (unnamed), and a daughter (Hanna). See below. So far, I have found no records for Marin, Werner, or Hanna.

Germany 1939 census:

Source: https://www.mappingthelives.org/bio/cda52d9d-c909-48ef-8ca4-71626147a874

Seydelstr. 3, Mitte, Mitte, Berlin

Date of Deportation: 21.08.1942