Love U Mother / Conversations Nobody Starts
The Arrangements Exist And You Should Ask Properly
Formal arrangements for decisions and affairs exist everywhere, and they differ everywhere.
There is a category of arrangement that families are vaguely aware of and almost never look into until it is needed: the formal mechanisms for who can act on someone's behalf, and how a person's wishes about their own affairs are recorded and given effect. These exist in some form in every jurisdiction. What they are called, what they cover, how they are made and what they require differ considerably from place to place, which is precisely why this is not something to take on secondhand advice about.
The plain guidance is this. These are legal and financial matters, and the people to speak to are a qualified professional in your parent's own jurisdiction and the relevant official authority for that place. Not a forum, not a relative who did it once in another state, and not a general article, including this one. What a magazine can usefully tell you is only that the arrangements exist, that they are ordinary and routine, and that they are much simpler to put in place while there is no urgency.
Two things are worth knowing culturally rather than technically. First, these arrangements are the person's own to make, and the earlier they are made the more clearly they reflect what that person actually wanted. Second, families who have them in place consistently describe relief rather than gloom, because a great deal of the anxiety in caring is uncertainty about who decides what. Getting proper advice is the entire action item here. Everything after that belongs to the professional you ask.