What horrible realization did Elie come to concerning Rabbi Eliahou?
The horrible realization that Eliezer comes to is more of a statement of what is as opposed to what should not be. In the factory, after evacuating Buna, Eliezer and his father take turns sleeping through the night. While awake, Eliezer sees Rabbi Eliahou in search of his son. Eliezer realizes that the son abandoned the father while on the run in the belief that the father would not make it and survive. The estrangement of father and son, and more pressingly, the abandonment of son from father fills Eliezer with a certain dread. He hopes that he would not do what the Rabbi's son did. He hopes that he will demonstrate the loyalty and commitment that the Rabbi's son so sorely lacked. The horrible realization that Eliezer might be experiencing subconsciously, and that we know as readers, is that the true horror of the Holocaust lies in this condition. While the Nazis and Hitler do represent evil, the very idea that any set of circumstances would demand that children abandon their parents in the name of mere survival represents the worst of the Holocaust. This realization- the severance of emotional connection and bonds to one another and to one's own blood- is something that haunts at Eliezer, and serves as a foreshadowing for his own predicament when his father takes a drastically fatal turn in his health.