He could also just be the general paramedic for the SS Troops there and in the surrounding areas.
I'd say the prosecution is overreaching with this
I'd find it circumspect if a sergeant was able to pick his duty location or know what was going on in Poland. The nature of what the camps evolved into weren't exactly common information to the average soldier.
It's iffy. Many people denied knowledge of the holocaust, the camps etc, but the later you go in the war the more unlikely that defence actually becomes. The scale was huge, regular army units (NOT just the SS) were involved in atrocities and mass executions, the millions of Jews were just the start of it and so many people were killed in so many different ways at so many different times by so many different people. If you lived a town over from a concentration camp there was a 0% chance that you didn't know what was going on there at least partially. There were almost a million members of the SS. Civilians were involved in transportation, rounding up of people, deportation, etc. Regular soldiers guarded columns of Soviet PoWs on long death marches to camps. Regular soldiers shot hundreds of thousands of surrendered soldiers or exacted vengeance on civilians for partisan uprisings.
All of these people moved around the country at various times, they would talk, administrators knew about it on many levels, they would talk, blah blah. There's no way you can keep a lid on this. Many would not be aware of the
full extent of it, certainly, but it's a really tough sell to say that knowledge of it wasn't widespread.
However, we don't know based off this article when this person joined the SS (i.e. death camps definitely not widespread or well known in the 30's, but common knowledge by '44), whether he volunteered or was conscripted, or whether he chose his posting. These and other facts will no doubt come out in the trial.