Is a Syrian pound loan, which was agreed to be repaid in dollars, and was converted on the same day to dollars due to travel, considered usury? Is there any error in sending money to the family in Syria by handing a friend's brother the amount in Syrian pounds in exchange for depositing its equivalent in dollars into the friend's account later at the exchange rate of the day of repayment?

The principle is that a loan is repaid in the same currency that was owed by the borrower. It is impermissible to agree at the time of the loan to repay in a different currency, as this constitutes a deferred exchange between two usurious items, and this is a prohibited form of Riba (usury). Modern banknotes have the same rulings as gold and silver, and it is a condition for currency exchange between two currencies that it be transacted hand-to-hand.

Therefore, if the debt was in Syrian pounds and you initially agreed to repay in dollars, this agreement is void and constitutes Riba. The solution is for him to lend you the amount in Syrian pounds, and you return the equivalent amount to him in Syrian pounds.

However, if the repayment due date arrived, and the debt was in Syrian pounds, and you both agreed that you would pay him its equivalent in another currency, such as dollars, there is no harm in that. This is because exchanging what is owed after it becomes due is permissible.

As for converting the money such that you borrow in Syrian pounds to pay your family, and then at the time of repayment, you pay in dollars at the exchange rate of that day, there is no harm in this, provided that the initial agreement was not to repay in dollars. Exchanging what is owed, such that the debt is in Syrian pounds and you agree with its owner at the time of repayment to settle it in another currency, is permissible.