What is the Shar’i (Islamic legal) position on a mother drawing up a rental contract for two apartments in the name of two of her children, given that the father is the original owner of them, and the father agreed to this under pressure, knowing that one of the apartments is inhabited by the questioner on the condition that its ownership transfers to his sister after the father’s death, while the other is inhabited by the father on the condition that its ownership transfers to the questioner after the mother’s death?

If the property registered in the mother's name was nominally owned by the father, then the rental process carried out by the mother is considered an "unauthorized transaction" (tasarruf fudooli). This transaction becomes valid if the owner approves it, as happened here.

The lease agreement is reviewed from two angles: 1. Lease Duration: If the contract is perpetual (i.e., it entails actual ownership due to the enduring right of the tenant and the meager rental price), then the contract is considered void for not specifying the duration. 2. Fairness Among Children: Granting ownership or leasing the two apartments to the two daughters without the other children is considered an exclusive allocation that is not permissible unless there is a legitimate justification. If the father passed away under these circumstances without justification, these apartments must be returned to the rest of the inheritance and divided according to the Sharia proportions.

Summary: If the lease is valid and fair, the two sisters can complete the lease term, because a lease does not terminate upon the death of the lessor or the lessee. If the lease is void, the two apartments must be returned to all heirs. If they agree to lease them to the two sisters, there is no harm, and each will have a share of the rent.