Your brother would call your husbands sister by her first name. Or, "my (sibling's) sister in law.
brother in law
Sister-in-Law
You would call your husband's younger brother a brother-in-law.
You might want to call her sister-in-law, even though to the best of my knowledge there is no officially designated relationship for this situation. But I am certain that she will be very happy to be accepted with the above designation.
The relationship of the sibling of your sister-in-law or brother-in-law to you does not have a name in English. You could call them your brother- or sister-in-law if you want, or you can call them the brother or sister of your brother- or sister-in-law.
You would call your sister's husband your brother-in-law.
you call her your daughter's husband's sister
Your sister-in-law is either the sister of your spouse or the wife of your brother. In either case, she would call you her brother-in-law.
How about your brother.
No. An Uncle is the brother of either your Mother or Father. You're kids may call him 'uncle'
Your brother's wife is your sister-in-law. You would refer to her and treat her as if she were your sister.
sister