The focal point of this story is Leo Finkle. He is the one who is searching for love and determined to start the next path of his life by finding the right love. Through him, readers are able to experience the struggle of a young adult desperately trying to understand himself and the world around him. It is through religion that Leo has learned to explain the world, but he is struggling with his faith and his ability to "come to God." Through his search for love, readers see his search to accept and embrace his faith.
If the focal point of the story was another character, then the themes mentioned would be lost. If, for example, Salzman was the focal, then readers would be experiencing the struggles of a parent with a disobedient child - a much different type of human conflict than the one outlined above.