If a person who is unable to speak conveys by sign that he has given some property on rent or he has rented some property, the rental agreement is valid.
Ruling 2190.* If a person leases a house, shop, or anything else, and the owner stipulates a condition that only he can use it, the lessee cannot sublet it to anyone else to use unless the new rental agreement is such that the use of the property is especially for the lessee, such as when a woman rents a house or a room and later gets married and gives the house or room on rent to her husband for her own residence there.
But, if the owner does not stipulate a condition [that only the lessee can make use of it], then the lessee can sublet it to another person. When handing the property over to the second lessee, the first lessee must, based on obligatory precaution (al‑iḥtiyāṭ al‑wājib), obtain authorisation from the owner.
However, if the first lessee wishes to give it on rent for a higher rental fee than what he has rented it for, then even though the payment may be in a different commodity, in the event that the property is a house, shop, or ship, he must do some work on it, such as making some repairs or doing some plastering, or he must have suffered a loss in looking after the property. And based on obligatory precaution, the additional rental fee must be commensurate with the work done or the loss suffered.