What can be done about violating a POA agreement?

The easiest way for things to be done and to be done quickly is to have your Father revoke the power of Attorney.  If your Father is not incompetent - and you say that he is indeed of sound mind - then have him send a letter by certified mail to the person who is the present Power of Attorney revoking the fiduciary duty he now holds.  Have him execute a new Power of Attorney - revoking all those executed in the past - and making sure that all financial institutions are aware of the change.  It would be advisable to go to the bank or banks with your Father and have them change the passwords or even close the present accounts and transfer the money to a new account that he has no access to at all.  If you want to call him on the carpet about his breaches of his fiduciary duties, speak with an attorney in your area about that to see if they are actionable.  Good luck.