Are the sisters entitled to demand money from the owner or from the sister who bought the deceased mother's apartment, on the grounds that it is an inheritance, and what is the legitimate position regarding this request and regarding accusing the sister of betrayal?

The old rental contract, which perpetuates the lease indefinitely, is Islamically invalid. The leased property must be returned to the owner without requiring any compensation, and this corrupt contract is not inherited from the lessor upon his death. Taking key money from the owner in this situation is considered unlawful appropriation of people's wealth. However, there is no objection to purchasing this apartment from the owner if it is done willingly after the leased property has been returned to him, so that the owner is not forced to sell due to his inability to evict the heirs under positive law. The heirs have no special privilege over others in purchasing if the owner is willing to sell and is able to dispose of his apartment.