Is the power of attorney issued in 2003 by the father to my brother concerning the residence still valid, or does it need to be changed?

Agency is when a person appoints another in his stead to perform a permissible and known transaction. It terminates due to five matters: the principal dismissing his agent, or the agent dismissing himself (with notification to the other party), the death of either party, the insanity of either of them, the subject of the agency going out of the principal's ownership, and the purpose of the agency being fulfilled.