I used to work with a Federal LEO whose Father-in-Law used a large number of German POWs on his farm in South Alabama.
He would give them cigarettes. They received Red Cross packages from Germany and they contained ersatz cigarettes which they would immediately throw away.
He told me that the old guy exchanged Christmas Cards with a large number of them until he died.
Being a POW in the United States was a bit different than the other way around.