Final answer:
The elderly man's primary concern in the wilderness is finding shelter and warmth to protect himself from extreme cold.
Step-by-step explanation:
The elderly man's primary concern in the wilderness is to find shelter and warmth. In the extreme cold, his main focus should be on protecting himself from hypothermia and frostbite. Building a fire and finding or constructing a shelter will help him stay warm and increase his chances of survival. He does not need to worry about finding a cellphone signal or social media updates, as his immediate priority is ensuring his own safety and well-being.