Is it permissible to marry a paternal cousin who was nursed by the elder sister of the prostrator (sajidah)?

If your cousin was suckled by your elder sister five full sucklings, he becomes your maternal uncle through suckling, and thus he is one of your mahrams (unmarriageable kin), and it is not permissible for you to marry him. However, if the suckling was less than five sucklings, the prohibition is not established, and it is permissible for you to marry him. If he and your sister were suckled by your mother, or your father's wife, or a woman who establishes mahramiya for you, then the prohibition is established between you. But if their wet nurse was a stranger who does not establish mahramiya for you, then it is not forbidden for you to marry him.