If your brother adopted you, you are his son or daughter and his in-laws are your grandparents by adoption.
No.
Not automatically. In most cases, the default laws of inheritance do not consider adopted siblings as heirs unless specifically mentioned in a will or estate plan. It's important to have a legally binding document outlining your wishes for inheritance to ensure your adopted brother receives what you want him to inherit.
Your brother to her would be a brother-in-law.
your mom's brother would be your uncle
your dad's brother would be your uncle
You would be 2nd cousins, assuming that the brother's wife's granddaughter is also the brother's granddaughter. If the granddaughter is not the granddaughter of the brother, there is no relationship.
Your wife's brother's son would be your nephew...
Your brother's children would be your nieces and nephews.
In most families he would be called your nephew. But there is no real relationship. Unless your brother adopts him, which would legally make him your nephew.
No, your brother's brother-in-law is not related to you unless you and your brother both married children of the same parents and they had another brother. but the the brother-in-law relationship is not through your brother and his marriage, but because he is the brother of your spouse. Technically, the proper introduction would be, "This is my brother's brother-in-law" as there is no direct relationship between the two of you.
lol... ur brother's adopted daughter would b ur niece... this is because no matter what, she is his child and any child that your brother or sister has would be your niece or nephew, the only way she can be a cousin is if it was one of your parents brothers or sisters who adopted her.
Your wife's brother is your brother-in-law, but in the English-speaking world the his wife is not related to you. It is common, however, for your children to consider her to be their aunt.