According to the Shariat law, a person can only leave one-third of their property to anyone they wish. The remaining two-thirds will, by law, go to their heir or heirs, equally shared between them.
Now, this is in case the person has more than one heir, and would like to leave an asset or property to just one of them. Although he can make a will asserting the fact that heir 1 will receive the asset, it will not be valid unless, after his death, heir 2 is willing to sign over the rights to heir 1.
However, one can always leave the one-third of their asset to anyone (and even heir 1), since it is acceptable, and does not require anybody’s consent.
Other considerations that are induced by the Muslim Law include:
a.A person can bequeath a property, even if he does not possess it at the time of writing the will, but has it in his possession at the time of death. (If not, of course, the will becomes null and void).
b.An individual cannot lay any conditions or requests on the bequeaths. The bequests have to be unconditional.
At the time of making the will, an individual needs to pick the persons who might execute his will. The request is taken into account at the time of disposal of assets. The person picked as an executor of the will has the right to dispose off the assets as specified in the will.