Kapos were prisoners in Nazi concentration camps who were selected by the SS guards to oversee and manage other prisoners. They were often chosen because they were considered to be more reliable or loyal to the guards. In some cases, kapos were given certain privileges or better treatment than other prisoners in exchange for their cooperation.
In the case of Elie Wiesel, the protagonist of the book "Night," he was assigned to work with a kapo who gave him easier work because he had shown himself to be a quick learner and was able to perform the tasks assigned to him efficiently. Additionally, the kapo may have seen potential in Wiesel to become a reliable worker, and may have wanted to build a good working relationship with him.
However, it is important to note that the actions of kapos were often motivated by self-preservation and a desire for personal gain. Kapos were also subject to the brutal and dehumanizing conditions of the concentration camps and could become violent and abusive towards other prisoners in order to maintain their position and avoid punishment by the guards.