The question refers to Shakespeare's Romeo and Juliet.
When Capulet says the words " "When the sun sets, the air doth drizzle dew"... he follows it by "But for the sunset of my brother's son..." - which shows is that he means his brother's son, Tybalt - that is the correct answer. Although he is not happy she is crying, he is satisfies that the reason is proper - she is allowed to mourn Tybalt.