I have twice had to deal with the affairs of relatives whose physical and mental states had deteriorated to such an extent that they were no longer able to manage their affairs but who had refused to complete POAs. In each case it made a bad situation dreadful, dealing with the sudden collapse of a household; caring for house, household bills, close relative in hospital and no access to the funds necessary to pay for utitilties, deal with domestic disasters (pipes bursting)
It meant that medical authorities would not speak to me, even though my relations wanted me to be told and, in one case, explain to my uncle, his wife's medical problems. I paid the care home fees for an aunt and uncle for three months, more than £6,000, while we sorted the POA out. I was able to claim it back, but it was fortunate that I had the money available.
I now see not setting up a POA as an act of monumental selfishness by the person refusing to do it, of utter disregard for those who that person claims to love and care about and who, at a time of distress and difficulty, will have this distress made even more distressing and difficulty because the person who is benefiting from the care of family and friends, really cares so little for them that they will not lift a finger to make that task easier.