No because you are not involved in the marriage. Your husband's or wife's sister would be your sister-in-law. Your son's mother in law is not related to you in any way.
No. The second wife is stepmother to a father's son from a first marriage.
Common-law marriage, or the thought that they are married do to long term living conditions, is not a legal marriage and cannot be used in a criminal offense when dealing with marriage law. If he is her son-in-law that means he is the legal husband of one of her daughters and it is reprehensable and adulterous that they would be doing this, but there is nothing illegal about it.
On 12th May 2010, the Allahabad High Court held that the marriage of a Muslim man to a Hindu girl as void. The Allahabad High Court declared, "For a valid Muslim marriage, both the spouses have to be Muslim."
No, he is your step-son.
Your grandfather's daughter-in-law could be your mother or your aunt by marriage. Your mother's brother is your uncle and his son is your first cousin. The brother of your aunt by marriage (the wife of an uncle) is not related to you, and neither is his son.
Stepson; Son in law; Brother?
She is the co-mother in law of you and your daughter's father in law is your co father in law. :-)
Your son-in-law's kids from a different marriage are often referred to as your step-grandchildren. They are not biologically related to you, but they are part of your extended family through marriage. You can also simply call them your son-in-law's children.
Your mother's son is you or your brother. Your mother's son's daughter is your daughter, or your niece. Your mother's son's daughter's mother is your wife, or your sister-in-law.
If your daughter-in-law's grandson is a child from a marriage before she married your son, or after their marriage ended, her grandson is not related to you. If he is a child of the marriage between your son and your daughter-in-law, then he is your great grandson.
I would think you would call her by her name, same as if she were your son's American mother-in-law.