I think that one of the unanswered questions would center on the family once Bruno dies. Essentially, we know that the father understands what happens and adopts a very nihilistic view towards being in the world as a result of it. An unanswered question is whether or not the family can unify after such an event. Along these lines would be that if the family does unify, what happens to them in terms of their relationship to the Nazis? The family never really spoke about what their role in the murder of millions was. With Bruno's death, do they now know of this role and with what they know, what is done with it? Additionally, how do Bruno's grandparents, already at odds with what their son is doing, approach the family, knowing that their child's actions ended up causing the death of their only grandson? I think that this might be an unanswered question. I think that the fundamental question that is left without a clear answer is what ends up happening to the family with the understanding of what the Nazi Party actually does and whether or not they resume their role as intermediaries or whether they actually take an active role against Nazism.
No offence but u couldve done the unanswered questions in teh missle of the book instead fo the event. but its okay it was sorta helpful