the Prophet (ﷺ) said: "It is not permissible for a woman to mourn for any deceased person for more than three days, except for her husband."
Sunan Ibn Majah Book 10, Hadith 70
← Previous Hadith he heard Zainab the daughter of Umm Salamah narrating that she heard Umm Salamah and Umm Habibah mention that a woman came to the Prophet (ﷺ) and said that her daughter's husband had died, and she was suffering from an eye disease, and she wanted to apply kohl to her eyes (as a remedy). The Messenger of Allah (ﷺ) said: "One of you would throw a she-camel's dropping when a year had passed (since the death of her husband. Rather it is four months and ten (days)."

Sunan Ibn Majah Book 10, Hadith 69 Next Hadith → the Messenger of Allah (ﷺ), said: "It is not permissible for a woman who believes in Allah and the Last Day to mourn for any deceased person for more than three days, except for her husband."

Sunan Ibn Majah Book 10, Hadith 71