Auschwitz postcards

[McSeam]

Today is the 72nd anniversary of the liberation of Auschwitz by the Red Army . Thank God it's happened!
I have three German postcards which were sent to and from the camp. It’s the correspondence between father and son. The son, Otto Koch, was an artilleryman, judging by his feldpost number but it's interesting for me who was his father, Richard Koch, in Auschwitz? The postal address was the following: Auschwitz 3 (Oberschlesien), Postschließfach 300. Seems he worked inside, somewhere in the camp. I don’t know German, so is it possible to find out anything about Richard by reading the letters?

The first:





The second:





The last one:

[HPL2008]

What makes you think the father had any connection to the camp?

Nothing in the contents of the postcards points in this direction, and his occupation is given as "Kaufmann" (merchant, trader, grocer or businessman).

I'd say he simply lived in Auschwitz. (The town, not the camp complex, that is.)

[McSeam]

The address.
At first the figure "3" in "Auschwitz 3". The town was just Auschwitz, but Auschwitz-3 was the camp, it was built in 1942-43 as a part of this huge camp complex.
Than "Post box 300". Seems that if it was just the town there were a street name and a house number in the address.
I think that Richard was not among SS- or miltary staff, but maybe a civilian worker?
Actually, could a civilian merchant who just lived in the town send feldpost letters?
I'm not sure, I just suppose.
You know much more than me about German postal address, so it's interesting to know your opinion.

[HPL2008]

The address.
At first the figure "3" in "Auschwitz 3". The town was just Auschwitz, but Auschwitz-3 was the camp, it was built in 1942-43 as a part of this huge camp complex.

Sorry, but no: This has nothing to do with Auschwitz-III (Monowitz); the "3" is simply the number of the post office in charge.

Than "Post box 300". Seems that if it was just the town there were a street name and a house number in the address.
I think that Richard was not among SS- or miltary staff, but maybe a civilian worker?

More likely is that he did not (or not yet at the time of writing) have a permanent address in Auschwitz, thus using a PO box. He writes in one card that his "room" (not house or apartment) is finished/done up, which would support that. Of course, it is possible that he was in town because he was doing some kind of business with the SS (he was a Kaufmann...), but nothing in these cards directly indicates that.

Actually, could a civilian merchant who just lived in the town send feldpost letters?

Yes, of course, as could any civilian who was in correspondence with a person serving with the German armed forces in an operational area. The Feldpost service transported all private mail for deployed military personnel, both sent by them and sent to them.

[McSeam]

Thank you for so full and quick reply, it's always interesting to find out something new!