This was because Zhao Chunxiang had seen what Li Yu had written in his letter. In it, he explained that he had learned the National Master, during a divination, explicitly stated there was only one Lucky Star. Between Li Yanyan and Xiaosuisui, one was certain to carry the Celestial Destiny. Li Yu had therefore advised his second brother to find someone to read their birth charts. Crucially, he urged his brother to ensure that, before the Li Family came to collect the Lucky Star, their mother was dissuaded from beating or scolding the two children.
Li's Fourth Son was aware of the rumors in recent years that Li Suisui was the reincarnation of an unlucky spirit, and that his mother had treated Suisui harshly over the years. He feared this Lucky Star designation might fall upon Suisui, and if this child grew up holding a grudge… That was why Li's Fourth Son had hinted at these concerns in his letter to Li's Second Son.
