What is the protagonists stage of identity development throughout the boy in the striped pajamas beginning middle end

At the beginning the boy ( Bruno) seems to like to be be heard because of his small argument with his father. In the middle, it could be said that a change of personality occurs, due to his friendship with Samuel. He finds out that Samuel is a Jew, however, he tries him in the same way, without paying attention to what her sister says to him. At the end, Bruno decides to stay with his friend even though it represents a great gender for him. He stands by his "best friend"