From Nikah to Waqf: Your Complete FAQ Guide

Yes.

A surviving spouse would first take his or her prescribed share from the estate. A wife’s Islamic inheritance share would be 1/4 (or 1/8 if the husband had children) of her husband's net estate. A husband’s Islamic inheritance share would be 1/2 (or 1/4 if the wife had children) of his wife's net estate. The balance left in the estate would go to the decedent’s surviving Islamic heirs like parents, children, or siblings.

But what happens if there are no other surviving Islamic heirs?

Except for Uthman Ibn Afan, who held that a spouse is entitled to share in radd like the other obligatory Islamic heir takers, the Shāfi’ī, Hanafī, Hanbalī, and Mālikī Schools hold that while spouses are obligatory heirs (ahl al-fara’id), they are not entitled to radd.

Today, the majority of Muslim countries, including Egypt, United Arab Emirates, and Jordan, provide that while they do not permit a spouse to take radd if there are any other surviving Islamic heirs, they do permit a spouse to take radd if there are no other surviving Islamic heirs. So if the sole surviving Islamic heir is a spouse, the spouse would take his or her Quranic share plus the balance remaining in the estate by radd.

A joint will that is also called a “mirror will,” “mutual will,” or “reciprocal will” is a will that may be executed by a married couple to ensure that their property is disposed of identically at time of death. In a standard joint will, the wife and husband make identical wills that provide when one spouse passes away, the surviving spouse receives everything, and when both of them pass away, the estate would be left to their children or other beneficiaries. Except for your spouse, American law allows you to leave your estate to anyone, and for the most part you are free to disinherit any family member (with a few exceptions in some states).

The Sharī‘a, on the other hand, is a fixed share system. You have restrictions on the distribution of your estate. The Sharī‘a has certain gender-specific obligations and the inheritance rights of each spouse's beneficiaries are different. For example, the parents of one spouse are not the legal heirs of the other spouse. The inheritance distribution of each spouse is also different. For these reasons, the Sharī‘a does not permit a person to leave his entire estate to the surviving spouse. For this fundamental reason, a joint will would violate the requirements of the Sharī‘a.