What are the rulings regarding suckling (radāʿa) in the following cases: 1. Does the nephew (sister's son) become the questioner's brother and his children's maternal uncle if the questioner's mother breastfed him? 2. Are the aunts of the nephew who was breastfed by his younger brother forbidden to the questioner and his siblings? 3. Is the grandmother of the nephew who was breastfed by his younger brother forbidden to the questioner and his siblings? 4. Are the questioner's children forbidden to his niece (sister's daughter) who is the sister of his nephew who was breastfed by the questioner's mother? 5. Is the questioner's sister forbidden to her husband (her sister's husband) due to suckling?

The one who suckles from a woman becomes her son and the son of her husband, the owner of the milk. This applies to the suckling infant only, not to his siblings. Any two who suckle from the same breast are siblings through suckling.

The nephew whom the mother suckled becomes a brother to the suckling child through fosterage, an uncle to his children, and a paternal cousin to them by lineage.

The aunts of the nephew whom the mother suckled are not forbidden to his foster-siblings, nor is his grandmother forbidden to anyone.

The children of the suckling woman are not forbidden to her niece, who is the sister of her nephew whom the mother suckled.

The second sister is not forbidden to the husband of the first sister if he is a foster-father to her brother whom her sister suckled, but combining the two sisters (in marriage) is forbidden.

These rulings are established by suckling that causes prohibition (of marriage), which consists of five satisfying sucklings within the first two years of life.