What is the ruling regarding the marriage of a man to the daughter of a woman who breastfed him, without him remembering the number of feedings, and the mother refuses to divorce her daughter from him?

Scholars have differed regarding the amount of breastfeeding that establishes prohibition [of marriage], and the preponderant opinion is that prohibition is not established except by five known breastfeedings, based on the hadith of Aisha (may Allah be pleased with her) that the ten breastfeedings were abrogated by five known ones. If there is doubt as to whether the breastfeedings reached five, then prohibition does not occur, because the default is its absence. Accordingly, there is no impediment to the continuation of the marriage as long as it is not proven that the breastfeedings reached five, though caution in matters of one's religion is preferable.