Is permissible to buy/sell with non-Muslim?
Yes buying/selling for a Muslim with non-Muslim is permissible as regards what is lawful.
Is it permissible for a wife to boycott (not to attend to his different needs) her husband?
It isn`t permissible for the woman to boycott her husband unless he is the reason behind that, and it is recommended that both spouses seek the advice of righteous people to make reconciliation.
Is it permissible for the heirs of the person who caused the accident (The Killer) to fast (The intended as an expiation for unintentional killing) on his behalf if the latter died in the crash?
All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
One who dies while liable for obligatory fast, his/her guardians have the choice to either fast on his/her behalf or feed one poor Muslim for each day of missed fast. This applies to Ramadan and other obligatory fast, and since expiatory fast is obligatory, feeding a poor person for each missed day or fasting on behalf of the deceased is obligatory as well. And Allah The Almighty Knows Best.
I have a question regarding the deferred portion of the dowry (Mahr)*. Is the wife entitled to it only upon divorce or she can claim it even if divorce hasn`t taken place? Moreover, does she have the right to claim this portion after death of husband, even if he didn`t divorce her before that?
All perfect praise be to Allah the Lord of The Worlds. May His blessings and peace be upon our Prophet Mohammad and upon all his family and companions.
In the marriage contract, it is recorded that the deferred portion of the dowry is due upon divorce or death, whatever comes first. If divorce took place first then the woman is entitled to it and if the husband died this amount must be paid from his estate. On the other hand, if the woman died then the husband becomes liable for this portion and it becomes part of the woman`s estate. We advise every husband to give this portion to his wife while alive because it is a right of hers. And Allah The Almighty Knows Best.
* In Islam, a Mahr is the obligation, in the form of money or possessions paid by the groom, to the bride at the time of Islamic marriage (payment also has circumstances on when and how to pay). While the mahr is often money, it can also be anything agreed upon by the bride such as jewelry, home goods, furniture, a dwelling or some land. Mahr is typically specified in the marriage contract signed upon marriage.
