FNB ditching a pensioner after almost 20 years of being a loyal client

My father had been a private wealth client with FNB for over a decade. He has been categorised as a Kayak client for more than 15 years now. He was accorded an overdraft facility for that length of time. His bond is at the same bank. He has purchased all my vehicles through Wesbank. He now banks his monthly pension with FNB without fail.

Recently, the overdraft of R66k was taken without prior warning/notification. The account was then handed over to the banks lawyers. How is this possible without any prior comms about the accounts overdraft standing? He feels completely mistreated by FNB. We have been trying to investigate the situuiton further without avail.