What is the ruling on the conditions agreed upon between the project owner and his in-laws? Does the man deserve anything after their breach of the agreement before the term expires? Does the contract become void because of this? Does he have the right to annul the contract due to their breach of the condition?

The seller's condition to his in-laws that he be their sole supplier of goods through murabaha leads to an unknown price for the project sale, thus invalidating the sale. Al-Ruhaibani said: "A condition that invalidates a sale; such as 'sell me this for one hundred, on condition that I mortgage this item to you for it, and for the other hundred you owe me'; due to the unknown price, because it is one hundred, and a benefit that is tied to the first hundred, which is unknown." Al-Mardawi said: "If an unknown is added to a known, or subtracted from it, the whole becomes unknown, and an unknown price invalidates the sale." The contracting parties must repent to Allah Almighty for engaging in this type of invalid contract and refer the matter to the Sharia judiciary or recognized scholars for resolution.