Thank you for the reply.
I have some new information.
My great uncle was stationed as a soldier in Rotterdam. The first child of him and Hermine must have been born in Rotterdam around 1940-1942.
He got in war captivity for a short time.
Hermine lived for a couple of years in Germany. She went back to the netherlands around 1945. At this time she was pregnant with a daughter. The son remained in Germany.
Between 1945-1947 the child was taken out of the house. The DRK had organized it.
I wrote to our city hall to get some more data about the time in witch Hermine lived in Germany. Perhaps I get some dore data about her and the son.