After the husband's sister got married, she had offspring with people from another family. The child is a direct descendant of another family and is in-laws. In popular parlance, it's called nephew.
If it is a child of a husband's brother's family (this brother includes brothers and cousins), then the child can be called a nephew; Besides, my husband and sister call you, and my husband's son is also called nephew.
Other titles:
1, aunts are called uncles.
Say "uncle/dad/dad" or something. Writing or being called "uncle".
My aunt and uncle are called uncles.
Say "uncle/uncle/aunt" or something. Writing or being called "uncle".
Auntie and Auntie are called Auntie.
Say "uncle/aunt/aunt" or something. In words or abroad, it is called "auntie".
4. Uncle and uncle are called uncle and aunt.
Say "uncle/aunt/aunt" or something. Call it "auntie" in words or outside.