He is your nephew, and you are his uncle.
There is no genealogical relationship. He is just your son-in-law's brother.
If your brother adopted you, you are his son or daughter and his in-laws are your grandparents by adoption.
your son and your brother's son will be cousins
your son is your brother's nephew, and your brother is your son's uncle
your son and your brother's son will be cousins
your son and your brother's son will be cousins
Your mother's son is your brother or your half brother.
Your wife's brother's son would be your nephew...
Your son's wife is your daughter-in-law. Her brother is your son's brother-in-law, but the English language has no word for a relationship between you and him. You are not considered to be related to him.
Your brother's son is your nephew. His wife is your brother's daughter-in-law but is not related to you.
If your wife's son is also your son, then he is your brother's nephew and your brother is his uncle.If your wife's son is a child from a previous, or subsequent marriage and is therefore not your son, he is not related to your brother unless you have adopted him. If you have adopted him, the relationship is the same as if he were your biological child.
If your wife's son is also your son, then he is your brother's nephew and your brother is his uncle.If your wife's son is a child from a previous, or subsequent marriage and is therefore not your son, he is not related to your brother unless you have adopted him. If you have adopted him, the relationship is the same as if he were your biological child.