The husband's brother is a brother-in-law to the wife. The wife's brother is a brother-in-law to the husband. However, the husband's brother is not related to the wife's brother.
They are brothers-in-law.
You are your brother's wife's brother-in-law, if you are male. But your brother's wife can also have brothers-in-law who are not related to you or to your brother. They would be the husband's of the wife's sisters.
There are two ways to have a brother-in-law. If you have a sister and she gets married, her husband is your brother-in-law. Also, if you get married and your wife has one or more brothers, they are your brothers-in-law.
His relationship to you is brother-in-law.
Your sister-in-law is either the wife of your brother or the sister of your spouse. Your brother-in-law is either the husband of your sister or the brother of your spouse. So your brother-in-law's wife is either your sister or is not related to you. Some people incorrectly refer to a brother-in-law's wife as a sister-in-law.
The brothers of your husband are your brothers-in-law.
Your wife's brother-in-law is either your brother or the husband of her sister. In the first case, her brother-in-law's brother is you or one of your other brothers. In the second case, her brother-in-law's brother is not related to you.
Your wife's brother-in-law is either your brother or the husband of her sister. In the first case, her brother-in-law's brother is you or one of your other brothers. In the second case, her brother-in-law's brother is not related to you.
Your husband's brother is your brother-in-law but his wife is not related to you.
Your brother's wife is your sister-in-law. Your spouse's sister is also called your sister-in-law. Your sibling's husband is your brother-in-law; your spouse's brother is also called your brother-in-law.
In the cultures based on the European languages, your wife's sister is your sister-in-law. Her husband is not related to you. In India, a wife's sister's husband may be called "Co-Brother."