In fact, children are insecure. I feel threatened. The original 100% love is now divided equally, even if it is fair, it is 50% less. Have a fixed time to accompany her every day, tell her stories, play with toys and chat. Let her know that her brother is still young and needs the help of adults. So sometimes mom and dad want to take care of their younger brother, but you are an adult. Sometimes they can even help us take care of our brothers together. Let her participate in the process of taking care of her brother. One is to cultivate feelings with her brother, and the other is to cultivate her sense of responsibility. Kill two birds with one stone.