One man married a girl. After marriage, the wife became mentally ill. She had two children who lived with their khala (aunt). Now 12 years of marriage have passed but there is no improvement in the wife's condition. Now the husband wants to marry her sister. Is this permitted according to Islam?
in Islamic rules, marriage with the sister of wife is forbidden and is not possible. the holy Quran explicitly refers to this judgment in Surah Nisa, verse:23, as follow:
حُرِّمَتْ عَلَیْکُمْ أُمَّهَاتُکُمْ وَ بَنَاتُکُمْ وَ أَخَوَاتُکُمْ وَ عَمَّاتُکُمْ وَ خَالاَتُکُمْ وَ بَنَاتُ الْأَخِ وَ بَنَاتُ الْأُخْتِ وَ أُمَّهَاتُکُمُ اللاَّتِی أَرْضَعْنَکُمْ وَ أَخَوَاتُکُمْ مِنَ الرَّضَاعَةِ وَ أُمَّهَاتُ نِسَائِکُمْ وَ رَبَائِبُکُمُ اللاَّتِی فِی حُجُورِکُمْ مِنْ نِسَائِکُمُ اللاَّتِی دَخَلْتُمْ بِهِنَّ فَإِنْ لَمْ تَکُونُوا دَخَلْتُمْ بِهِنَّ فَلاَ جُنَاحَ عَلَیْکُمْ وَ حَلاَئِلُ أَبْنَائِکُمُ الَّذِینَ مِنْ أَصْلاَبِکُمْ وَ أَنْ تَجْمَعُوا بَیْنَ الْأُخْتَیْنِ إِلاَّ مَا قَدْ سَلَفَ إِنَّ اللَّهَ کَانَ غَفُوراً رَحِیماً
- Forbidden to you are your mothers and your daughters and your sisters and your paternal aunts and your maternal aunts and brothers' daughters and sisters' daughters and your mothers that have suckled you and your foster-sisters and mothers of your wives and your step-daughters who are in your guardianship, (born) of your wives to whom you have gone in, but if you have not gone in to them, there is no blame on you (in marrying them), and the wives of your sons who are of your own loins and that you should have two sisters together, except what has already passed; surely Allah is Forgiving, Merciful.
man can marry with the sister of his wife in some cases as follow:
if the first wife dies.
if the first wife divorced by husband.
in above question, presupposition is that the wife is Alive and is not divorces but she is mental.in that case, if man want to marry with her sister, then he must conduct according to this rules such that either man put a way first wife or expect to die his wife.
Imam Khomeini, Tahrir Al vasilah, vol.2.p.280