Where is Commandant Breuer taking Reuven?

The Commandant says that he is taking Reuven to his mother. As his mother is dead, we can infer that the Commandant means for Reuven to join her in death. He has been "chosen".

Then he picked Reuven up. "A boy your age should be with his mother," he said, smiling. "So I shall be sure you go to her."