If two people are brother and sister and the sister has a son, then:
her brother is her son's uncle, and
her son is her brother's nephew.
The sister's son would be the nephew of her brother.
If your sister-in-law is the wife of your brother, she is the mother of your brother's son. Her son-in-law would then be the brother-in-law of your brother's son. If your sister-in-law is your spouse's sister, her son-in-law is not related to you or to your brother's son.
If your sister-in-law is the sister of your spouse, her son is not related to your sister's son. If your sister-in-law is the wife of your brother, her son and your sister's son are first cousins.
If your niece's is by your sister but the brother is by your sisters new husband & another woman there would be no blood relation. If not then he's the nephew
Your sister's son is your nephew.
If your daughter's brother-in-law is the brother of your son-in-law he is not otherwise related to you.If your daughter's brother-in-law is husband of her sister, then he is your son-in-law.
Real sister, half sister, or step sister
Yes, for a nephew is sister's son, brother's son, wife's brother's son, wife's sister's son, husband's brother's son, husband's sister's son
It is your sister's or brother's son, your adopted sister's or brother's son or your half sister's or brother's son. That would make you an aunt or uncle.
The son of your brother or sister is your nephew.It is your nephew
Your mother's son is you or your brother. Your mother's son's daughter is your daughter, or your niece. Your mother's son's daughter's mother is your wife, or your sister-in-law.
Your sister-in-law's son is your nephew.