I think we may be getting mixed up between two cases now... jugnage's father, and JoostvD's friend.

jugnage's's father was born in Germany, in 1941, to Polish parents who - reading between the lines - were living in Germany as forced labourers. He had German citizenship when he arrived in the USA in 1947. How he acquired German citizenship when his parents' were not German is an interesting question, but he did. (There was no German state in 1947... who would have been responsible for issuing travel documents to German residents at that time?)

JoostvD's's friend was born in South Africa to German Jewish parents who left Germany in 1939. His case appears to be identical to several cases I know of people who were able to acquire German citizenship because their parents were victims of Nazi persecution. JoostvD's, I'm afraid I don't have any web links - this is just something I've always known, ever since I was a child (long before the Internet was invented!) as I have always known people who were in that situation.