Information kindly provided by Hanna Lincoln nee Bohnsack
Drafted the day war broke out. Served on the Russian front. Joined Medical Corps but refused commission. Medical Officer in a convalescent home in the High Mountains. Apparently killed returning from leave when his train hit a mine (source: two officers who lived locally and were on the train with him)
His daughter Hanna recalled that he had several brothers, and thinks they died in WW1.
Wilhelm Christian Bohnsack Drawn by an artist at Dnjepropetrowsk, Reichskommissariat Ukraine (now Dnipro, Ukraine). The braid around the shoulderboards confirm him as an NCO (non-commissioned officer), but the part denoting rank was not drawn so he could have been Unteroffizier, Unterfeldwebel, Feldwebel or Oberfeldwebel. The collar tabs were common to many ranks, but as a medical man the dark lines would have been blue.
‘Dnjepropetowsk’ is an old spelling for the Ukrainian city of Dnipropetrovsk, and there was indeed a POW camp (kriegsgefangenenlager) there. From Jan 1942 – Feb 1943 it was called Stalag 348 (source https://www.moosburg.org/info/stalag/laglist.html ) which from what his daughter Hanna related (2016) is likely to be where the portrait was drawn.