How did the actions of the Winslow family tell the purpose of the story?

Ronnie is blessed with a family who believe in him and who know his character even when confronted with an accusation that he is dishonest. Catherine, his sister, does not even need to think about the accusations, she knows that they are untrue. Her father is also convinced of his son's innocence and does not think twice about challenging the government and the Navy in his defense.