Is it permissible for a son to sell his father's land in the UAE to support his sister and pay for his mother's gold that the father seized, knowing that the father is withholding financial support and threatening to reclaim what he previously spent?

The son must fulfill the trust his father placed in him, and it is not permissible for him to take anything from his father's money without his permission.

University study expenses are not considered obligatory maintenance upon the father, but the maintenance of children is obligatory upon him if they are in need of it.

If the father refuses to pay the obligatory maintenance to those for whom maintenance is due, and the son is able to access his father's money, then he may take from it the amount of his maintenance in a reasonable manner, just as Hind was permitted to take from her husband's money according to the hadith: "Take what suffices you and your child in a reasonable manner."

However, the entrusted son is not the rightful owner and it is not within his authority to take rights.