1a. My mother’s new husband is my stepfather.
2a. My sister’s husband is my brother-in-law.
3b. My son’s wife is my daughter-in-law.
4b. My father’s wife’s daughter is my stepsister.
1a. My mother’s new husband is my stepfather.
2a. My sister’s husband is my brother-in-law.
3b. My son’s wife is my daughter-in-law.
4b. My father’s wife’s daughter is my stepsister.