What should I call my brother-in-law and daughter-in-law?

Sister in law. The so-called brother-in-law, that is, the wife's brother, but when people speak or say hello, they generally don't need to call him brother-in-law, and most of them call him brother like a wife or call him by his first name. In this way, the daughter-in-law of the brother-in-law can also call her by her wife's name, such as calling her sister, and of course, calling her sister by her first name.