Is it permissible for a person to grant one of his heirs a property during his lifetime, while retaining the right to usufruct it for life?

The general rule is that a gift (hiba) cannot be made contingent upon a condition, according to the majority of scholars. Furthermore, it does not become binding except upon possession. So, if the giver dies before possession, the gift becomes void. If the gift is to one of the children, then justice must be observed among all the children. And if the intention behind the gift is to disinherit an heir, then it is forbidden (haram).

However, if the giver says: "This property is for so-and-so after my death," this is a will (wasiyya), and it is forbidden if it is for an heir, due to the Prophet's (peace be upon him) saying: "Indeed, Allah has given every rightful person his right, so there is no will for an heir," unless the other heirs permit it.