Is it permissible for a father to designate his son's share of a joint project established on land for which the son paid the price, and for the father to distribute his share of the aforementioned property to his heirs exclusively, as a will to be executed after his death? And is it permissible for him to bequeath to his deceased son's children within the one-third limit or to place them in their father's stead?

If your son becomes your partner in a project, he has partnership rights to the capital and profits according to the agreement. His share must be specified to preserve his right and prevent disputes.

It is not permissible to distribute your share of the project to your heirs during your lifetime through a will that takes effect after your death, because the Prophet, peace and blessings be upon him, said: "There is no will for an heir."

However, you may distribute this part of your wealth among your children justly during your lifetime, or gift it to whomever you wish while you are alive and healthy.

Treating grandchildren as their father's equivalent in a will is not sound if their share exceeds one-third. The will for them should be within the limits of one-third unless the heirs agree otherwise.