The ruling on covering up from the husband of one’s sister to one who was breastfed by her sister

Question:
She says: I was breastfed by my sister along with her daughter. Then, when I grew up, I did not cover up from her husband. What is your guidance for me now? May Allah reward you with good.

Answer:
If you were breastfed by your sister five times or more, and you were a small child within the two-year period before weaning, then you are her daughter. She is your mother and your sister, and her husband is a mahram (a relative one may not marry) to you; because you are his daughter through breastfeeding, if you were breastfed from her milk while she was with him. If it was from a husband before him, then you are his stepdaughter, a stepdaughter to him, the daughter of his wife, if he had intercourse with your mother and had relations with her. So the result is that you are his daughter if the milk was his, or his stepdaughter if you were breastfed from the milk of a husband before him.
If the breastfeeding was five times or more while you were within the two-year period before being weaned, that is the case. But if the breastfeeding was less than that, then no, you are not a mahram to him. Rather, you are the sister of his wife. You do not become a mahram to him unless the breastfeeding is complete, five times or more, while you are within the two-year period. Yes.

The presenter: May Allah reward you with good, and may He do you good.