The Sister-In-Law Who Occupies the Magpie's Nest

My brother has been married for ten years and has very little savings, so he spends all of his money on medical treatment for his sister-in-law and his family. After finally saving up the down payment for the house, my sister-in-law asked to leave a room at home for my sister. So that she can live in it for a long time in the future. How come my brother agrees to this? He slapped the table: "If Xiaoyun moves in, Xiaoxiao should move in too!" His sister-in-law said angrily: "How can she compare with Xiaoyun? She will get married in the future!!"