If your family was advised by the Red Cross of his capture, then they would have the record for him. They have approximately 36 million individual cards on POW's from WW2. It can take quite a while to get a response from the Red Cross, but luckily they have most of the records. However, the International Red Cross had closed the archives for conservation work since January 2014. They should be reopening it sometime soon for research requests. I would suggest contacting them to see if they have a date yet when they will start to accept requests-
https://www.icrc.org/eng/resources/documents/article/other/0...https://www.dd-wast.de/en/home.htmlDeutsche Dienststelle (WASt) is the German government office for military records and information on German troops who were missing in action or PoW's.