That would be the relationship. If she were to adopt him, son would be correct.
That is the term.
She is not the biological mother but is the wife of the biological father.
By his first name :) He is his stepson or after adaptation he becomes his fosterson.
The mother of your wife is your mother-in-law.
Yes, if she is not your biological mother
His girl friend now used to be his wife Claudia Valdez and his stepson but he call him his son Frankie.
Unless you are in a polygamous marriage, you are your husband's wife, so you would call her your mother.
The bride should discuss with her biological mother how she would feel if her ex husband's common law wife was invited to the wedding. If the biological mother is comfortable with this then there is no reason not to invite the common law wife. If the biological mother is dating someone special or is remarried and bringing her mate to the wedding then you should ask your father and his common law wife without discussing it with your mother.
Your mother-in-law.
If you are close to your step-brother, or to his wife, you can call her your sister-in-law. If you are not close, you can call her your "step-brother's wife."
Your aunt's mother is your grandmother. Her father is your great grandfather and his wife is your great grandmother. Unless he remarried after your great grand mother was born. In that case his wife is either your step-great grand motehr or is not related to you at all, depending on how you want to put it.
Mother, if you mean wife of the deceased husband.
I would just call her my second mother