Is it permissible for the questioner's sister to marry the younger brother of the questioner's paternal cousin, who was suckled by the questioner's mother?

Whoever is suckled by a woman five known sucklings, that woman becomes his mother by suckling, and her children become his siblings by suckling. As for the rest of his siblings, they are not his siblings by suckling. Therefore, the aforementioned Aisha is not Muhammad's sister by suckling, so it is permissible for him to marry her unless there is another legal impediment.