Why can Shun ascend to the throne?

"Shangshu" said that when Emperor Yao chose his successor and asked for your opinions, everyone chose Shun among the people. When Emperor Yao asked about Shun's ability and moral integrity, the person who recommended Shun stated that his family environment was very bad: his father was blind, his temper was strange and his mind was not right; His mother likes to lie; His brother is too arrogant and always makes trouble. It is in such a family that Shun can live in harmony with the whole family and let them turn evil into good. Because Shun has the virtue and ability to manage his family well, Yao gave him the throne of the country.