All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
We praise Allah, The Exalted, for guiding you to His religion, and we ask Him to bless us and you with steadfastness on it until death. As for the questions, our answers are summarized as follows:
1) It has been confirmed to us that when a Muslim, who lives in a Western country, does not state in his will that he wishes to be buried in an Islamic way (according to the Sharee‘ah) and his family are disbelievers, his body is submitted to them after his death, and they can arrange his burial in whatever manner they decide. They either cremate him or perform the funeral prayer in a church or elsewhere according to their religion and the system applied in their country. If this is the case, then it is incumbent on a Muslim to write a notarized will stating that his body must be submitted to Muslims at one of the Islamic centers, to be buried in an Islamic way and to organize a funeral prayer for him/her in accordance with the Sharee‘ah.
2) Also, when a Muslim does not state in his will the manner in which his estate should be handled, his estate is divided among his family members (according to the applicable laws). However, it is well-known that a non-Muslim is not entitled to inherit from a Muslim, as per the Sharee‘ah. Therefore, it is incumbent on a Muslim to write a will stating that his estate must be divided in accordance with the Sharee‘ah
3) It is permissible for a Muslim who has no legitimate heirs to bequest his whole estate to whatever charitable causes he wishes. Ibn Al-Qayyim said: “If an ill person who has no heir wishes to bequest all of his wealth in charity, is he allowed to do so? There are two opinions in this regard, the correct opinion of which is that he is allowed to do so because the Sharee‘ah only forbids him from making a bequest of more than a third of the estate when he has legitimate heirs. So, the one who has no legitimate heirs may do whatever he wishes with his wealth without objection.” [End of quote]
4) A Muslim is not sinful for making a bequest in favor of his disbelieving relatives. The Mother of the Believers Safiyyah bint Huyayy made a bequest in favor of some of her Jewish relatives. This was narrated by Al-Bayhaqi in As-Sunan Al-Kubra, in the chapter entitled: “Bequests Made in Favor of the Disbelievers.” Moreover, it was said regarding the interpretation of the verse (which means): {…except that you may do to your close associates a kindness [through bequest]} [Quran 33:6] that it was revealed about the bequest of a Muslim in favor of his Jewish and Christian relatives. Accordingly, it is permissible for a Muslim to make a bequest in favor of a disbeliever. What is forbidden is for a disbeliever to inherit from a Muslim, and there is a difference between a bequest and inheritance.
5) You should not delegate a disbeliever to execute your will after your death, whether concerning the burial procedures or the division of your estate as stated in the will. You should rather delegate a Muslim to execute it. You may delegate one of the Islamic centers, for example, because the conformity in the religion urges the executor to give utmost care to the proper execution of the will, unlike a disbeliever, who may care less for its execution and is not to be trusted with such a task.
6) There is no sin on a Muslim for offering a gift to his disbelieving relative, and he may accept a gift from a disbeliever as well. It was authentically narrated by Al-Bukhari and Muslim that ‘Umar ibn Al-Khattaab gifted a garment to his brother who was a disbeliever residing in Makkah. Scholars deduced from this that it is permissible for a Muslim to give a gift to a polytheist. It was further narrated in Musnad Ahmad that Qutaylah bint ‘Abd Al-‘Uzza, who was a disbeliever, came to visit her daughter, Asmaa’ bint Abu Bakr, may Allaah be pleased with her, and had some gifts for her. Asmaa’, however, did not accept her gifts or admit her into the house. ‘Aa’ishah asked the Prophet about that. Thereupon, Allah, The Exalted, revealed the verse wherein He Says (what means): {Allah does not forbid you from those who do not fight you because of religion and do not expel you from your homes…} [Quran 60:8] The Prophet commanded Asmaa’ to accept her mother’s gifts and admit her into her house.
7) There is no specific wording for the will prescribed by the Sharee‘ah. A person may write his will in whatever wording that suits what he wants to state in it.
Allah Knows best.