How to save elderly relatives who keep falling for scams

My family knows about cashier's check scams and other crafty international methods of loosing the elderly and other emotionally fragile types from their money. Over the past few months, both my husband's great uncle and his sister's ailing landlord have been the subject of a series of shysters and hopeful perpetrators of fraud; and despite a great deal of effort on my husband's part, no law enforcement officials, banks or wire services helped in the least. Fortunately, my husband has talked them out of sending money in each case.