I want to Zainab bint Jahsh when her brother died. She asked for perfume and used some of it and said, "By Allah, I am not in need of perfume, but I have heard Allah's Messenger (ﷺ) saying on the pulpit, 'It is not lawful for a lady who believes in Allah and the last day to mourn for more than three days except for her husband for whom she should mourn for four months and ten days.'"
Sahih al-Bukhari Book 68, Hadith 80
← Previous Hadith Zainab bint Abu Salama told me these three narrations: Zainab said: I went to Um Habiba, the wife of the Prophet (ﷺ) when her father, Abu- Sufyan bin Herb had died. Um ,Habiba asked for a perfume which contained yellow scent (Khaluq) or some other scent, and she first perfumed one of the girls with it and then rubbed her cheeks with it and said, "By Allah, I am not in need of perfume, but I have heard Allah's Messenger (ﷺ) saying, 'It is not lawful for a lady who believes in Allah and the Last Day to mourn for a dead person for more than three days unless he is her husband for whom she should mourn for four months and ten days.'"

Sahih al-Bukhari Book 68, Hadith 79 Next Hadith → "I heard my mother, Um Salama saying that a woman came to Allah's Messenger (ﷺ) and said, "O Allah's Messenger (ﷺ)! The husband of my daughter has died and she is suffering from an eye disease, can she apply kohl to her eye?" Allah's Messenger (ﷺ) replied, "No," twice or thrice. (Every time she repeated her question) he said, "No." Then Allah's Messenger (ﷺ) added, "It is just a matter of four months and ten days. In the Pre-Islamic Period of ignorance a widow among you should throw a globe of dung when one year has elapsed."

Sahih al-Bukhari Book 68, Hadith 81