Wa`alykum As-Salaamu Warahmatullahi Wabarakaatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear brother in Islam, we would like to thank you for the great confidence you place in us, and we implore Allah Almighty to help us serve His cause and render our work for His Sake.
First of all, it is be noted that Islam demands its adherents to show patience and acceptance of Allah’s will when they face the calamity of the death of a relative. Therefore, it forbade them from all acts and sayings that show discontent and dissatisfaction with Allah’s verdict such as wailing, tearing clothes, etc.
The eyes of the Prophet (peace and blessings be upon him) shed tears for the death of his son, Ibrahim, and he said: “O Ibrahim, our eyes shed tears and our hearts are filled with grief, but we do not say anything except that by which Allah is pleased. O Ibrahim, we are grieved for you.”
As regards your question, the late Sheikh Hassanain Makhluf, former Mufti of Egypt, states the following:
Every Muslim and Muslimah should receive the death (of a relative or an associate) patiently showing their acceptance of Allah’s verdict. The maximum period of mourning for a woman is four months and ten days, if the deceased is her husband, and three days for relatives and other persons. It is impermissible for a woman to exceed these periods for the Prophet, peace and blessings be upon him, said: “It is not legal for a woman who believes in Allah and the Last Day to mourn for more than three days for any dead person except her husband, for whom she should mourn for four months and ten days.”
Mourning is done by avoiding ornaments and perfumes, etc. not by crying, wailing, slapping the cheeks, shaving hair, and other forbidden acts. Wearing black clothes as a sign of mourning is only permissible within the period of mourning.”
Elaborating on the concept of mourning from an Islamic point of view and its limitation, we would like to quote the following:
Different societies have different customs and traditions associated with death in the family. In non-Islamic societies, there are visible signs of mourning which are supposed to convey grief. People, especially women, should wear black for a certain period, according to the degree of their relation with the deceased. Men may wear a black tie, etc. In certain communities, death is marked by loud crying and tearing of clothes, etc. All this is forbidden in Islam. This does not preclude that people may grieve for their deceased and they may express their grief with shedding tears. This sort of crying must not be accompanied by wailing. That is un-Islamic.
The maximum period of mourning for a woman is three days, if the deceased is a very close relation to her, but not her husband. In other words, mourning for a deceased father, son or brother may be only over a period of three days, after that, she must show her acceptance of Allah’s verdict. We have a report of two cases of the Prophet’s wives, Um Habiba and Zaynab. The first lost her father, Abu Sufyan, and the other lost her brother.
After three days, in each case, each of them requested perfume to wear. Both of them said that they had no desire whatsoever to wear perfume, but they had heard the Prophet saying: “It is not legal for a woman who believes in Allah and the Last Day to mourn for more than three days for any dead person except her husband, for whom she should mourn for four months and ten days.” As you realize, this is the length of the waiting period of a widow. During her waiting period, she must not wear make-up.
The above quotation is excerpted with slight modifications from www.islamicity.com
Allah Almighty knows best.