A Power of Attorney and a 'representation agreement' of some kind need to be in place so that if he shows signs of greatly diminished capacity the PoA or representation can be plunked down on the bank/hospital admissions desktops and that person can act. It's a safety net, and it's a dignified way of preserving the heretofore wishes and normal behaviours of the patient. It sounds like this needs to be done immediately because he is slipping in his ability to represent himself in deciding who should act on his behalf for medical interventions and for financial decisions. I hope he has a valid and updated will.