What is the ruling on working in the shop of the paternal grandfather who previously expelled his mother? And is it permissible to claim the warehouse that was built with private funds on land that the father had gifted and then retracted his gift?

1. It is permissible for the son to work in his father's shop with his permission. Customary permission suffices if the father sees him and does not object. However, he is obliged to leave or pay rent if the father requests it.

2. The father's gift of the storeroom to his son is not complete merely by declaration; rather, it requires attestation. If the gift is proven and subsequently altered by the son building upon it with his own money, the father is not permitted to revoke it. The prohibition is further emphasized if the revocation is to give the gift to another child, as this involves enticement and sowing enmity among the children. Therefore, the son is permitted to claim ownership of the storeroom.

3. The son must advise his father kindly regarding his mockery of religion and its rituals, as this constitutes disbelief that expels one from the faith. If he does not respond, the son should seek help from people of knowledge and righteousness, and supplicate frequently for him.