Without looking at the chart, given his address in 1936, the spelling and the general impression of the letter, I doubt that he was ever wealthy. The Veedel was never wealthy, but always a melting pot.
Oh, BTW, in relation to the suggestion above that the name of the street would indicate a Jewish quarter: the street is named for the Benedictine’s Cloister of the Holy Maccabees.
Ernst Ries was literally living next door across the street to the Ursulinenschule, a catholic school for girls.
In the same house, at least in 1941, lived Margarete Rolef, born Silberstein, Carl/Karl Rolef,
and her daughter Margot Rolef, all deported to Riga on the 6th of December 1941. Karl reportedly died in April 1945 in Stutthof, nothing is known about the deaths of his family. They are remembered in Yad Vashem.
This gives you an impression how the street looked in 1915.
