The best answer is to stay healthy. Only your father can change his power of attorney. If he’s not competent to do so now, your only option is to organize other family members or friends to step in in the event you become incapacitated. They would probably have to seek a court-ordered conservator to supersede the successor attorney-in-fact. For information on guardianships and conservatorships, go here: http://www.elderlawanswers.com/guardianship-and-conservatorship-12096.