The State of North Carolina may very well have a division that handles such complaints and investigates without cost to you. Even if they do, of course they will take time doing it.
Any one with "standing" or technically the right to complain, can file suit to challenge the power of attorney and/or have the current agent removed for breach of "fiduciary duty." As his son with ultimate rights of distribution as a descendant, you should have that "standing." Of course you will need a North Carolina attorney. ( I assume that is where your aunt is)>
This comment does not create an attorney-client relationship. The law and its application by the courts is constantly evolving and changing. This discussion is not to be taken as a definitive guide, and should not be relied upon to determine all fact situations. Each set of facts must be examined separately with the current case and statutory law analyzed and applied accordingly.
If an agent under a power of attorney is acting inappropriately then court action is required to remove such individual and procure the assets which have been misappropriated. I suggest that you contact an attorney immediately to put a stop to this behaviour.