Is it permissible for a woman to shake hands with her brother-in-law?
It is forbidden for the woman to shake hands with her brother-in-law because he isn`t a Mahram (unmarriageable) of hers.
My brother works in a conventional bank and gave me one of the gifts distributed to bank employees — what is the ruling on accepting it?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
There is no objection to accepting such gifts, because the physical gift itself does not carry any inherent prohibition — unlike stolen property. Sin does not transfer or extend to the one who receives the gift, for Allah the Almighty says {what means}: "And no bearer of burdens shall bear the burden of another." [Al-Anʿām/164]
The evidence for this is that the Prophet ﷺ himself ate from the food of the Jews, conducted transactions with them, and purchased from them — and it is well known that their wealth was intermingled with ribā. Similarly, the wealth of conventional ribā-based banks is a mixture of the lawful and the unlawful.
Ibn Ḥajar al-Haytamī, may Allah have mercy upon him, states: "It is not forbidden to transact with one whose wealth is predominantly unlawful, nor to eat from it — as al-Nawawī affirmed in al-Majmūʿ." [Tuḥfat al-Muḥtāj, Vol. 9/P.389] And Allah the Almighty knows best.
Is it permissible for the children of a deceased father to settle his debt from the Zakah (obligatory charity) money due on them?
It is impermissible to use the Zakah of one`s money for settling the debts of the deceased. However, children should settle the debts of their deceased parents out of filial piety. And Allah Knows Best.
Is it permissible to offer an Udhiyah on behalf of another without their permission?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
It is not permissible for a person to offer a sacrifice (Udhiyah) on behalf of someone else without their permission, except in the following cases: if he sacrifices on behalf of the members of his household, if a guardian sacrifices from his own wealth on behalf of his ward, or if the Imam (ruler) sacrifices from the public treasury (Bayt al-Mal) on behalf of the Muslims. And Allah the Almighty knows best.