While your province may have a particular law regarding powers of attorney, generally the attorney can be asked to produce an account of transactions made while using the power of attorney. If there is dissatisfaction with the report, interested parties can apply to have the attorney removed. It might also be possible for certain persons (who will be defined by each province's law) to simply apply to court for the power of attorney to be ended. The court would then consider the evidence and decide what is in the best interests of the person who gave the power of attorney.