Several of the characters in After the Dancing Days show a high degree of empathy. At first, Uncle Paul seems to be the most empathetic character, but after his death, the protagonist, Annie Metcalf, exhibits the greatest empathy, inspired by his example.
After the Dancing Days is primarily a Bildungsroman, which describes the emotional and intellectual growth of Annie Metcalf during and immediately after the First World War. Along with her mother and father, Annie's Uncle Paul is the most important figure in her life, largely because he shows empathy for her.
It may be that Uncle Paul is the most empathetic character in the novel, but he has limited scope to display this quality. However, Annie is the protagonist, and we see her empathy develop over time. Much of this growth takes place after Paul's death. Because Annie is the central character, the reader sees more of her interior life than that of other characters. This means that more time and space are devoted to exploring the empathy, which becomes one of her most marked characteristics, making her appear the most empathetic character by the end of the narrative.