He was overly compliant and cooperative with their attempt to steal his money (yes, “steal”; if they took it under a pretense and won’t give it to him what is that but theft). His response should have been “Then close my account right now. This second. I want every penny.”
Legally, once you deposit funds in a bank, it is NO LONGER your money. It is the bank’s, and you just have a lien on it, similar to the mortgage they hold, on the home you own.