Norrad - maybe, just maybe, Peter had a medical emergency leaving him a bit confused, flustered, and with some loss of memory. Maybe, a person living in a home around where the car is - is caring for him. Maybe that person has NO idea Peter is being searched for. Don't know the area but it sounds remote and some residents may not have a TV. I would go knocking on the doors near where the car was left and see if he is in someone's home. So sorry this has happened, our elderly are so precious.
OR - is there anyone who was angry about the upcoming wedding? just a thought