Clearly, Qin Yuzhen doesn't have an invitation. She has been estranged from Qin Han for many years. Although every New Year, Qin Yuzhen calls her brother to offer greetings, Qin Han barely acknowledges her before hanging up. The last time Qin Yuzhen pleaded with Qin Han to find a job for Luo Chao, he only managed to find a security position for him, indicating how poor their sibling relationship really is.
As a result, Qin Han absolutely wouldn't send an invitation to Qin Yuzhen, and Luo Chao understands that his mom came uninvited, all because he called her.
Luo Chao somewhat regrets telling his mom about Qin Han's grandson's full-month banquet, but he can't entirely blame himself because his mom often nags in his ear about the job his uncle found for him, emphasizing the importance of gratitude and paying back favors.
So Luo Chao called his mom, asking whether they should send a gift to return the favor, hoping to avoid his mom nagging him about it in the future.
