Fritz Fraenkel was a chemical engineer in Berlin. In February 1936, he emigrated to Heerde in the Netherlands. In November 1939, he moved to Epe and in December 1939 to Amsterdam. On 24 Feb 1943, he was sent to the concentration camp Vught (Herzogenbusch) and on 21 March 1943 to Westerbork. According to one source, he was in Auschwitz before being sent to the labour camp Dörnhau (Kolce, Gmina Głuszyca, Poland), which belonged to the concentration camp Groß Rosen. According to an index card in the Arolsen Archives "Judenrat Amsterdam" collection, he died on 20 April 1945.
Fritz Fraenkel's mother was Ernstine [later Ernestine] Fraenkel née Schaul, b. 6 Mar 1877 in Kempen/Posen (Kępno, Poland). Her husband Leopold, a baker, was born in Schloppe (Człopa, Poland) on 16 Mar 1871. Leopold, Ernstine and their son Erich emigrated to Brazil. Leopold and Ernstine died in Rio de Janeiro on 31 Jan 1944 and 9 Jan 1968, respectively; I could not find further information about Erich.
Fritz Fraenkel married Esther Aronson on 31 Dec 1940 in Amsterdam. She was the daughter of Meijer Aronson (b. 7 Jan 1878 Amersfoort, d. 14 Sep 1942 Auschwitz, Shoah victim) and his wife Jansje Ketellapper (b. 16 Nov 1879 Amsterdam, d. 3 July 1960 Amsterdam, survivor). Esther survived (I don't know where and how) and lived in Amsterdam again in August 1945. In September 1947 she moved to Den Haag, and in April 1954 she went to the United States. She died in San Francisco on 1 Sep 1999.
Sources: Stadsarchief Amsterdam, Archiefkaarten; Social Security Death Index (USA); Bundesarchiv Gedenkbuch (Germany); Arolsen Archives (Germany); Berlin civil registers; JewishGen Online Worldwide Burial Register; Family Search, Brazil immigration cards and civil registers