Answered by Shaykh Amjad Rasheed
I used to be a non-Muslim and alhamdulillah accepted Islam. I was born an orphan and my [h: adopted] parents adopted me while I was a child. If I die, what is the ruling of my parents inheriting from my wealth, keeping in mind that, unlike myself, they have not accepted Islam. What happens if I die and I don’t have any spouse or child? Who is the rightful heir of my wealth?
[h: Islamically speaking, there are two main means by which ownership of property is transferred after the death of the owner: (1) bequests (wasiyya) and (2) inheritance (irth). The difference between them is explained in section L1.0 of The Reliance of the Traveller. One can dispose of a maximum of one-third of one’s property by bequest; the rest is disposed of according to the laws of inheritance. Only specific relatives, who must be Muslim, can inherit. Others, including non-Muslims, can receive bequests.]
A non-Muslim cannot inherit from a Muslim, nor can a Muslim inherit from a non-Muslim, regardless of whether he or she is one’s father, son, or some other relative. If an orphan’s guardian does not have a reason to inherit from the orphan in his or her custody [h: by his or her being a rightful heir by virtue of his or her blood relationship to the orphan, for example], he or she may not inherit from the one under his or her charge, regardless of whether he or she is Muslim or non-Muslim. However, it is permissible for a Muslim to make a bequest that one-third (or less) of his or her wealth be given to his or her non-Muslim parents or his or her guardian, even if he or she is not a Muslim.
If a Muslim dies without leaving any rightful heir, such as a wife, husband, children, parents, or someone else [h: for a complete list of rightful heirs, see Reliance, L6.2], or if they exist but they are all non-Muslim, then his or her money becomes the property of the Muslim common fund (bayt al-mal). If there is no common fund [h: as in our times today], then it is the responsibility of the righteous Muslims to distribute it to the poor and needy. If someone in this situation is wealthy, I would advise him or her to avidly spend some of his or her wealth over a period of time for the interests of Muslims. By doing so, he or she will have given a tremendous charity and served his or her Muslim brothers and sisters. [h: When giving his or her money in charity, he or she should be careful to] keep in mind his or her personal needs as well [h: and not give so much charity that would cause his or her personal needs to go unfulfilled], thereby gaining both benefits. This is better than leaving one’s plenteous wealth to be played with by untrustworthy hands after one dies. One should also make a bequest [h: by writing a will, for example] that one’s wealth be distributed after one’s death to Islamic avenues and benefits. One should appoint a godfearing and knowledgeable person whom one trusts as an executor of this bequest.
(Translated by Hamza Karamali and Moustafa Elqabbany)