How were belgian and luxembourgish POW treated?

Hello Indy and the team!

My great-grandfather was a belgian POW but I don’t know much about his time in german prison/ labour camp because he didn’t talk to me about it and he died when I was young. I have been told that he was freed earlier or got better treatment or something like that because he talks luxembourgish (he lived on the border with Luxembourg), which was seen as “germanic”.

Could you comment on the treatment and date of liberation (if any) of POW from western power and how/if it was influenced by the language people talked and/or their place of origin? I am especially interested in Belgium and Luxembourg.