Patrick, an orthopedic surgeon, agreed to loan his brother Bobby $450,000 so that Bobby could start his own business. Bobby signed a promissory note, agreeing to repay Patrick $450,000 together with a market rate of interest on the unpaid balance. As a result of the failure of his business two years later, Bobby did not repay Patrick. One of the reasons Bobbys business failed was that his primary customer declared bankruptcy and was unable to pay Bobby the $500,000 he owed him. Bobby is currently insolvent. Any deduction for Patrick? Under what circumstances, if any, could Bobby claim a deduction for the amount of debt owed to him by his customer?