Hi Helen
I did a search at the site of Jewish cemeteries in Sao Paulo. I found a burial of Abraham Israel Blumberg, on July, 21,1945. Son of Benjamin and Bertha Blumberg. I wonder if he is the person you are looking for. See attached info.
No burials of Mordka Popower, Sara Popower, Sura Blumberg, Mauritz or Mauricio Popower, Elza or Elsa Popower, Margot Chmielnik.