He—may Allah have mercy on him—was asked:

“Two full sisters have children: one has two daughters, and the other has a son. The elder daughter was breastfed together with the boy. May he marry the daughter who was not breastfed?”

He replied:

If one daughter was breastfed by the boy’s mother, but he was not breastfed by her mother, he may marry her sister, by agreement of the Muslims.

He—may Allah have mercy on him—was asked:

“A woman left her daughter in the care of her brother’s wife and went away. When she returned, she asked, ‘Did you breastfeed her?’ Her brother’s wife said, ‘No,’ and swore to that effect. Later, her brother’s son grew up, as did her younger daughter. The girl’s sister had been breastfed together with his brother, who wishes to marry her. Is this permissible?”

He replied:

If the girl was not breastfed by the suitor’s mother, nor the suitor by her mother, they may marry one another, even if her brother and sisters were breastfed by the suitor’s mother. This has no bearing on the matter, by the consensus of the Muslims. Rather, when a child is breastfed by