Marion, I'm relieved!
Jean, I'm sorry. Your mail of the 2nd was locked and in my spam folder, I just found it. And what a mail! In the file brother Hubertus and Father Reginhard are mentioned, and both are also mentioned in sister Edeltrud's article in the book we talked about! Reginhard Spilker (2 mistakes on the form) was Prior-Administrator of the abbey from 1968-70, and both men were in the hospital in the war. With his name I found another text of Karl-Heinz Neifer from Siegburg who served as acolyte with Reginald Spilker in the hospital! Mr Neifer has finished his text series last year because he feels to old to continue his research, he has also interviewed Sr. Edeltrud, but he writes that he will help anyone who wants to continue his work 
I'm nearly sure that had no contact to the prisoners, but perhaps re remembers other interesting things? I will try to contact him the next days and then, if he allows, try to translate the main parts of his text.
Christoph