My great-grandfather is also from Danzig, so this was interesting to me.
I found this web site where it shows in Zoppot, Cecilienstrasse = Czyżewskiego http://www.danzig-online.pl/nazwy/uliced.html
If you can find an old map online from the era you are searching and compare it to a modern Polish map, you can see where it is .
If you Google Cecilien Strasse Danzig you get a lot of results.
This worked for me many years ago when I went to Shanghai. Armed with a map from 1939 and a modern one, I was able to locate all the places my parents lived, worked and hung out during WW2.