Can my mom sue the bank for not telling her that her husband was being scammed in a e-mail scam, being they had a joint acc. they told here nothing!

My dad just happened to be the "chairman of the board " at the same bank, so the bank kept it hush, hush, did a investigation, determined that he was being frauded, they tried to get back the money they sent, knowing he was being frauded, but in there own words in a investigation memo between two big wig pricks, they said they sent it anyway because of his position. They told my mom nothing about the fraud, the money transfer, or the reason why they were kicked out of the bank.2 months later the bank confinscates his computer, kicks him off the board, buys him a new computer for his retirement party, but still nobody tells my mom !!!!!!!!!!!! about the fraud!!!! Long story short my father goes from one bank to another after he send hugs sums of there money to these fraudsters, the next bank kicks them out so he goes to the next and they let him do it again and agian. In six months these banks watched my dad give away all there money . Western Union are also pieces of crap!!!!