Ruling on marrying one's father's stepdaughter or his wife's mother

Question:
My father married the wife of my brother's son after his death, several years later. He had a son and two daughters from her. I want to marry her daughter, who is from her previous husband. Is that permissible or not?

Answer:
Yes, there is nothing wrong with it. If your father married the wife of your brother's son, or married your brother's wife after his divorce from her, or after his death, or married his uncle's or maternal uncle's wife, there is no harm. You may marry the daughter of a wife who is not your father's, whether that daughter is from a husband before him or a husband after him. She is a stranger to you; she is only a stepdaughter to your father, whom he does not marry. As for you, she is a stranger. If a man marries a woman and his son marries her daughter or her mother, there is no harm.