What is the legitimate Sharia status of an apartment that was finished at the personal expense of the questioner in his father's property, and is the money spent on finishing considered a debt owed by the father, especially given that the questioner contributed a portion of the money to the construction of the property as a "loan" that has lost its value?

Resolving disputes falls within the purview of the Sharia courts or their representatives, as they are best equipped to hear all parties and ascertain the truth. A Mufti, however, hears only from one side. A mere permission from a father for his son to utilize an apartment does not establish ownership for the son unless the father explicitly declares it a gift or a transfer of ownership. The son's actions in furnishing and finishing the apartment have a standing value, not a depreciated one, provided it was done with the father's knowledge and permission. As for a debt, it is repaid in kind and is not tied to price levels, unless the currency's value depreciates significantly and unjustly. In such a case, the currency's value is taken into consideration if there is an excessive injustice or a collapse that causes harm to the creditor.