The original question had to be edited. I invite you to submit the other part in a separate question, for it is a great one. The absence of the Khaddish's recitation for Akiba Drumer is significant. It reflects the condition of those who were forced to endure the Holocaust. Wiesel makes it clear that one of the most brutal realities of the Holocaust was how the perpetrators were able to silence and dehumanize their intended targets. The narrative of the Holocaust gains greater levels of fear and brutality when it is clear that those in the position of power succeeded in their intentions.
The forgetting of the Khaddish for Akiba Drumer is one such instant. Wiesel is able to show how those who were in the Holocaust were dehumanized to such a point that many relinquished bonds between one another. The absence of the Khaddish shows this. Akiba Drumer, a rabbi who has lost his faith with what he has seen in the camps, asks those who are left behind to recite the prayer for him. Yet, those who are left behind are so consumed with survival, with meeting basic needs, and with merely existing, that they fail to do so. In this detail's inclusion, Wiesel wishes to show the brutality of the Holocaust. Outside of the massive amount of death and destruction, the true pain of the Holocaust was how many individuals were forced to surrender the connections to one another. When Eliezer says that they forgot to recite the prayer for Akiba Drumer, it becomes a reminder of what the Holocaust means for so many who were forced to endure it. The dehumanization and severing of community become the testaments of the Holocaust that are signified by the forgetting of the recitation of the Khadish for Akiba Drumer.