Read The Forgotten Soldier by Paul Sajer. It tells the story of an Alsatian who was dragooned into the Wehrmacht in the autumn of 1942 and ended up in the Panzergrendadierregiment Grossdeutschland. His unit was at Belgorad on the southern shoulder of the Kursk salient when operation Zitadelle began. Right next to the Grossdeutschland were battalions of Hitlerjugend who had been specially trained to infiltrate "Ivan's" positions.
The Belgorad offensive became a disaster after several days, of course, but it would be interesting to know Ratzinger's unit history in the Wehrmacht. At the close of the war, units in the West began to collapse as the Americans and the British approached. Germans understood that they could surrender to the Anglo-Americans. Units in the East stayed together under the most trying circumstances, as surrender meant death or Siberia.
Be Seeing You,
Chris