All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The gift (Hibah) is not effective and the wish of the deceased by itself does not suffice concerning this, as he died before completing it. A gift is not effective except after being possessed by the person to whom it is given as we have already clarified in Fatwa 108342.
The father passed away before dividing the land and transferring the ownership. Therefore, the gift is not valid and there is no consideration for the consent of the heirs in the gift being effective because it became invalidated before becoming effective and becoming binding.
Whatever he had left is considered as inheritance. If the heirs decide to agree to divide the inheritance according to what the deceased had determined, then it is permissible for them to do so if they all have a sound mind and are adults. However, it would be better to divide the inheritance according to the Islamic inheritance laws.
Allaah Knows best.