Is it permissible for the paternal uncle's daughter, who was nursed by the mother, to marry one of the maternal aunt's sons? And are the wife's paternal half-brothers considered her milk-siblings to the paternal uncle's daughter? And does the maternal aunt's first son become a milk-sibling to the sister?

If a woman breastfeeds a child five full feedings before the age of two, the child becomes her son through fosterage (rada'a), and it becomes unlawful for him to marry anyone who is unlawful for her biological children. However, this prohibition is specific to thew fostered child and his descendants, and does not extend to his brothers, sisters, or those above him, such as his father and mother.

Therefore: 1. Your paternal cousin's daughter, whom your mother breastfed, is not unlawful for your maternal aunt's sons through fosterage. 2. If your mother's milk was produced as a result of your father's intercourse with her, then your father becomes a father to your paternal cousin's daughter, and his children become her siblings. 3. It is unlawful for all of your maternal aunt's children to marry your sister who was breastfed by their mother.