If he gave up $15,180 in silver (based on spot price of $23 per ounce, spot changes minute to minute based on many factors such as worldwide demand), it means that he actually owes the rental people $15,108,000. This is a rare unicorn, this solvent silver sovvy, and this is his version of taping $3.00 of junk silver to a letter to the gas company. If I were the creditor, I would test the silver bullion or rounds with an acid kit and then accept it as a partial payment, if genuine. This unicorn might be the only sovvy ever to actually offer anything fungible to pay off a debt. They could take him to court for the rest, but that slot machine of crazy only pays out once. Write it off as bad debt for tax purposes.