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.
According to the view of the majority of the scholars a hiring contract is a contract which both parties are obliged to fulfil, and this contract is not invalidated by the death of one of the contracting parties. Therefore, if the hiring person dies and leaves a valid hiring contract, the rights of this contract are transferred to his heirs, and all his heirs are permitted to benefit from the rented property until the end of the period of the contract. Hence, an heir has no right to take control of the benefit over other heirs, even if this heir had worked with the deceased in the rented shop.
If this person had taken his wages for working in the shop, then he has no right in the shop or in any other property except his share like any other son. If he had not taken his wages and had worked as a volunteer with his father, then he is not entitled to anything. If he had not volunteered, he is entitled to the wages of a person who does the same job like him if there was no contract between him and his father which states another salary either greater or smaller than the wages of a person who does the same job like him.
For more benefit, please refer to Fatwa 90535.
Allaah Knows best.