All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
The wife of one’s brother is not unmarriageable to him forever; rather, as soon as the marriage between her and her husband ends through divorce or death and her ‘Iddah (waiting period) lapses, it becomes permissible for the brother of her ex-husband to marry her.