When a Muslim husband dies, the wife is supposed to be in Iddah for four months and ten days. Does anyone from the husband's side need to read a "NIYYA" for the Iddah?
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
A woman, whose husband has died, does not need any intention of mourning and does not need anybody to read it. She begins her period of 'Iddah (woman's prescribed waiting period after her husband's death) immediately after her husband's death. She must mourn her husband for four months and ten days. Mourning means a woman should remain at her husband's home, avoid using adornments such as perfumes and the like. In regard to a servant, if he is pubescent, she should not uncover herself before him whether before or after her husband's death. She must avoid being alone with him. Negligence in this matter may lead to bad results. In fact, unpleasant accidents are innumerable in this concern.
Allah knows best.
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