According to the article in Amtsblatt Chemnitz:
Über Schickstale “stolpern, 24 August 2018, p. 4 at chemnitz- amtsblatt/pdf
Betti Oppenheim-Maron was the grandmother of the children at this address -- Stefani Caecilie Mandel and Inge Elisabeth Mandel. Betti's daughter, Anni Oppenheim, married Emanuel Mandel, and they had two children.
Anni Mandel-Oppenheim and Emanuel/Enoch Mandel did not go to the Netherlands. Both were deported from Berlin on 19 February 1943 to Auschwitz, where they were murdered. Source: Yad Vashem Database & German Federal Archives.