How does the novel end? What is Wiesel's tone?

Night ends with the retreat of the Germans and the liberation of Eliezer and the other prisoners. Wiesel states that among the prisoners there is no real thought of taking revenge. All of them are in a state of starvation, so all anyone wants to do is eat. "Our first thought as free men was to throw ourselves on the provisions." The only thing besides getting bread that "some of the young men" do involves going into the nearby city of Weimar "to sleep with girls."
Wiesel relates that at this point he became seriously ill and spent two weeks in a hospital hovering between life and death. When he recovers enough to stand up, he looks in the mirror and states that "a corpse stared back at me."
His point is that a genocide survivor becomes, in effect, one of the living dead. There is no happiness for him, despite his liberation. Those in this situation typically suffer from what is now known as PTSD (Post Traumatic Stress Disorder), an ongoing condition from which few recover fully, if at all. They also have what is called "survivor's guilt." The inner question of "why did I survive when the others did not?" is unanswerable. Wiesel never sees his mother and sister again after the initial separation of men and women upon arrival at the camp. His father died on the death march as the prisoners were being tranferred west before the advancing Russian army. Night concludes darkly with the absence of any joy or even relief. Instead there is only lasting trauma, numbness, and bafflement at the cruelty and genocide that has been seen by the survivor.

The novel ends with Elie describing how the prisoners' resistance movement defeated the SS officers shortly before American soldiers liberated them from Buchenwald at six o'clock. Elie goes on to describe how the emaciated prisoners could only think of food and not revenge. After Elie gets food poisoning, he recalls looking at his reflection in the mirror and staring directly at a corpse, which is something that he will never forget.
The tone of the ending of the story is somber, melancholy, and pessimistic. Elie's horrific, traumatizing experiences in the German concentration camps have ruined his childhood and dramatically impacted his life. The last scene depicting Elie staring at his emaciated, corpse-like reflection is sobering and dramatic. Elie's melancholy tone reflects how the Holocaust has emotionally, physically, and psychologically damaged him.