In Night, what did author Elie Wiesel need to survive his experience of the Holocaust?

In Night by Elie Wiesel, Eliezer needed to stay as healthy as possible and to have a lot of luck in order to survive the Holocaust. Many others were not so lucky. Entire families were destroyed by the Nazi killing machine. Elie was fortunate because he first of all survived the initial selection when he arrived at Auschwitz. Secondly, Elie was lucky to get into a working unit at Buna where the work was relatively easy. Many other prisoners were worked to death building walls, digging trenches for graves, and doing all kinds of manual labor with little food. Many others gave up and died. Elie had his father to think of, so he kept hope alive for both of them. Without that hope of someday finding freedom, he may have well died, too. He also had luck on his side when he was able to have the operation on his foot. The Nazis often sent the sick and injured straight to the gas chambers. There seemed to be no rhyme or reason for who lived and who died. It was really just luck and a little hope that made the difference for Elie.