The guest is Levin’s brother Nikolai, who is thin and wasted, although he claims that his health is improved. Nikolai says that he is no longer with Marya, the prostitute, and Levin tells Nikolai about his farm improvements; what neither brother says is that Nikolai is dying. When Levin goes to bed, all he can think of is death and his inability to help his brother.
All of Levin’s improvements around the farm and his investment in his peasants’ lives seem utterly unimportant when faced with the physical reality of his brother’s illness: instead of thinking about the greater humanity, Levin is overwhelmed by his own emotions. He does not separate his feelings from his thoughts.