I think those disappearances were to slave camps or failed attempts to flee cause they weren't found after the war.

Also I don't think they were drafted. The kids were into Hitler youth and most were ok with going to fight. They would have warning and tell their friends they were going. Then before getting a gun surrender to Americans to become a burden on us. Literally one of my grandpa's always says he volunteered because he was sick of working so hard, we were fun he worked two days a week.