Is it permissible for the questioner to hold on to the structure he built on his father's land, for which his father gave him permission to complete, in order to guarantee his financial rights and the effort he put into it, and what is the fate of these rights after his father's death?

Therefore, a father's permission to his son to build on his land without explicitly transferring ownership to him is considered an 'ariya (loan), and it is absolute if no specific duration is stipulated.

Scholars have differed regarding the ruling on the value of the construction when the land is reclaimed: Hanafi school: The owner may remove the borrower from his land, and the borrower is compelled to uproot the plants and demolish the structure. The lender is not liable for anything. Shafi'i and Hanbali schools: The lender may reclaim the land, but the borrower is not obligated to uproot trees or demolish structures if doing so would diminish their value. The lender may take them with their standing value, or uproot them while guaranteeing any resulting depreciation. Maliki school: The borrower is compelled to uproot or demolish, and he is only entitled to the value of the dismantled structure.

The most preponderant opinion: Is that of the Shafi'i and Hanbali schools. Thus, the father may demand the land back in exchange for paying the son the cost of the standing structures. If he insists on demolition, he must guarantee any resulting depreciation. The siblings have no right to demand anything from the son because the land belongs to the father.