What are the pronouns for brother and sister in ancient poetry?

Hello. In front of outsiders, the elder brother calls the younger sister Shi, and the younger sister calls the older brother the elder brother of the family. In person, a brother calls his sister "little sister" or by his first name, and a sister calls her brother "brother" or "brother."

"Brothers and sisters" are eldest brother, younger brother, eldest sister and younger sister. "Brother and sister" refers to the brother's wife. When the ancients called two people brother and sister, they also called them brother and sister, which is no different from us modern people.

I hope it can help you, thank you and hope to adopt it.