What is the ruling of Sharia regarding the repayment of a loan taken in Syrian Lira in 2011, when the lender is now demanding it in US Dollars, knowing that the value of the Syrian currency has significantly deteriorated?

The value of the currency should be considered when settling deferred rights in cases of egregious exploitation or currency collapse, provided that the creditor or rights holder suffers significant harm, in order to achieve justice in disputes between the creditor and the debtor in exceptional circumstances. There is no harm for the creditor to return more than his due to the debtor upon repayment, out of good judgment, if it is not based on a condition or obligation. It is permissible to repay a debt firmly established as due with a currency other than the one the debtor received, if agreed upon at the time of repayment, and it is preferable for it to be at the exchange rate on the day of repayment.