Is it obligatory to remove accumulated usurious money from the father's inheritance, and what is the ruling on spending it on building a house or on education? Is it permissible to give this money to the widowed mother, and are rent and utility bills considered among its [legitimate] expenditures? Is zakat obligatory upon the orphan and the widow? And is it permissible to maintain a usurious bank account out of necessity?

The father erred by placing his money in an interest-based bank, and the son is repeating the mistake by keeping his share in it. It must be withdrawn immediately. It is permissible to open a current account in an interest-based bank if there is a future need. The heirs' share of the money is only the principal, while the interest is ill-gotten wealth that should be spent on the welfare of Muslims, such as the poor, the needy, and hospitals. It is permissible for poor and needy heirs to benefit from it. Zakat is obligatory on the share of each heir if it reaches the nisab (minimum threshold) by itself or with other funds, excluding the interest-based earnings. Zakat is obligatory on the widow, and the majority of scholars hold that zakat is obligatory on the wealth of a child. After reaching puberty, zakat is obligatorily agreed upon. Whatever was consumed from the interest-based earnings must be given in charity as an equivalent amount when one is wealthy, but it is not obligatory in a state of poverty.