This may sound strange, but I've heard and seen the name Friedrich in my searches, and you and I may have a connection somewhere with the name Kunigunde. I have a Kunigunde in my line, but she was a Fostel (maiden name, I believe) who may have married into the Fenzel family. We should compare notes. And the date of 1913 rings a bell and would seem to fit the timeline as well. I'm going through my notes and letters now to see if I can find something a little more concrete for you to work with.
Please feel free to contact me if you need some help with your German translation. I took it for 6 years in school and I even went to Germany as a foreign exchange student in 1990.