Question
A woman breastfed her sister's daughter along with her own daughter, and the aunt of her daughter from nursing is asking about the ruling in Islamic law, knowing that the child was breastfed until she was full?
Answer
I say, and with God's success: The uncle of her daughter by lineage is also an uncle to her daughter by breastfeeding; because the husband of the breastfeeding woman has become a father to the girl who was breastfed, so marriage between them is not permissible, and God knows best.