I had him confused with Prince Wilhelm Karl, who actually died fairly recently - in the last 20 years or so - and who must have been a young child early 1930s.
yes, Prince Wilhelm Karl lived from 1922 to 2007.
He was a cousin of Princes Wilhelm, the pretender, and Louis Ferdinand. But his father was Prince Oskar, the last Emperor‘s fifth son - that’s why Wilhelm Karl was so much younger than his cousins 🙂
I also had a cousin who was twenty years my junior…