How can debt be repaid if the value of real estate purchased with the borrowed amount changes over time, and would the creditor's demand for the current value of the property be considered usury?

The intention of the man who gave money to his friends must be considered. If he gifted it to them, then he has no right to demand it back, as it falls under the prohibited act of retracting a gift. However, if it was a loan, then the real estate and its growth belong to the friends, and they are only obligated to repay the borrowed amount without any increase. Both parties are encouraged to be lenient in their dealings. It is commendable for the friends to reward their friend with gifts, as Islamic law encourages giving gifts and showing appreciation.