There are several themes intertwined that are closely related. Change and transformation are certainly involved in this story of a recovering alcoholic who is desperate to get his daughter back from his dead wife's sister and her husband. But there is also guilt, and money at the heart of the story.
Charles is dealing with several crises at one time, the death of his wife, his guilt and feelings of responsibility for her death, the loss of his financial stability due to the crash of 1929. He is also mourning his lost life, the life he had before the crash, the irresponsible, wild life of drinking, not worrying about tomorrow. He actually feels guilty about how much money he was able to make during the stock market boom.
Charlie struggles with his conscience over Helen's death. They had argued about her behavior, her kissing another man in front of him, flaunting her ability to make him jealous. He went home and locked her out of the apartment. Helen walked all the way to her sister's house in a driving snowstorm, soaking her to the skin. Helen dies as a result of heart trouble, not pneumonia.
Charlie also has to resist the temptation to return to his old life, his friends are still drinking and partying, buy he must remain sober so that he can satisfy the court's requirement for him to get Honoria back from Marion Peters, her legal guardian.