In "The Boy In The Striped Pajamas," why does Bruno's family have to move?
In the book, Bruno's family has to move because his father has been ordered to relocate on the orders of the Fury (the Fuhrer, Adolph Hitler). Essentially, Bruno's father has been promoted to a Commandant position at Auschwitz, and this is why the family has to leave their house in Berlin.
Bruno doesn't especially like Auschwitz (which he calls Out-With), as he misses his grandparents and his friends. Also, he yearns for the familiar surroundings of his previous life in Berlin. Bruno's father humors him for a time, but he resolutely expects Bruno to resign himself to the family's new situation. As commandant, Bruno's father has an especially important position, and he must not fail in his tasks. The family's livelihood and survival depend on Bruno's father fulfilling his orders to the letter.
So, this is part of the reason why Bruno's father cannot entertain at length any complaints from Bruno. Like everyone else, Bruno's father must submit himself to the Fuhrer's demands or risk his wrath and certain reprisal for any failure to comply.