What is the remaining value of the debt: Is it 7,0 pounds, or another value determined by the average rent of 2 qirats multiplied by the time period until the day of payment of dues, plus the selling price of 2 qirats as of today? And if it were 7,0 pounds and the cousin was not satisfied with this amount, is it permissible to give it out as charity on his behalf?

There remains a debt of 7,0 EGP on your father for the remaining price of the Qirats. He is not obliged to pay rent for the land or to re-evaluate the price of the two Qirats at today's rate, as his delay in payment does not permit imposing an increase on him.

However, given the depreciation of the currency, some scholars deem compensation obligatory. If your father is in financial difficulty (ma'sir), he owes half of the difference. If he is procrastinating (mumāṭil), he owes the full compensation. The compensation is calculated by comparing the value of the debt to a stable currency such as the dollar (for example: if 7,0 EGP was equivalent to 2,0 dollars previously, and now it is equivalent to 226 dollars, the difference is 1,774 dollars).

This amount is paid in full if he is procrastinating, and half if he is in financial difficulty. It is preferable to pay the entire sum (the 7,0 EGP and the compensation) in a currency other than the Egyptian Pound, to avoid any resemblance of usury (riba).

If your uncle refuses to accept the money, it should be given to an intermediary or through the court. Donating it as charity is not sufficient.