His sister's son is called nephew. Just like your sister's son, your sister's son. His brother's son is called nephew. Just like your brother's son, your brother's son. Nephews and nephews are children of brothers and sisters of themselves or their relatives. Simply put, a nephew has the same surname as himself or his relatives, but the difference is a nephew.
Addresses of other relatives:
Grandpa: Grandpa, grandpa, grandpa.
Grandma: Grandma, grandma, grandma, grandma.
Great grandfather (grandfather's father): grandfather, great grandfather.
Great-grandmother (grandpa's mother): grandma and great-grandmother.
Mother-in-law: Call "mother" in person and "mother-in-law" in front of others.
Father-in-law: Call him "Dad" to his face and "Father-in-law" in front of others.
Mother-in-law: Call her "mother" to her face and "mother-in-law" in front of others.
Father-in-law: Call him "Dad" to his face and "Father-in-law" in front of others.
Dad's brother: Uncle, and his wife are called "Empress".
Dad's sister: Aunt, her husband's name is "uncle".
Dad's brother is called "uncle" and "big", and his wife is called "aunt".
Mother's brother: Uncle, his wife's name is Aunt.
Mom's sister: Auntie, my husband is called "Uncle".