Is Allah's decree inevitable regarding the divorce of the aforementioned woman? And what is the ruling on one who indirectly causes a divorce, as in the case of threatening the husband to take his sister, whereupon the husband responds by saying: "Keep her with you; she is divorced by three [irrevocable pronouncements]"?

Everything that happens in the universe, including divorce, is predestined and inscribed in the Preserved Tablet fifty thousand years before the creation of the heavens and the earth. A man's statement to his wife's sister that she will live with him is not an unlawful attempt to separate the spouses. However, he does not have the right to take his sister in simply because her husband married another woman, nor does the wife have the right to leave her home for this reason.