If your brother-in-law is the brother of your wife, then his brother-in-law is you.If your brother-in-law is the husband of your sister, then his brother-in-law is you or one of your other brothers....
If your brother-in-law is the brother of your spouse, his brother is also your brother-in-law. The daughter is your spouse's niece and therefore your niece as well.If your brother-in-law is the...
Your brother's brother in law would be your brother in law as well.
If you are referring to your brother's brother-in-law from his wife's side of the family- they are not related to you.