Short story reply to your question. Tell them to cook whatever is there and hope it stays edible long enough to keep them fed a while. I would not really count on you getting home in the normal time frame. Multiply that by a factor of 10 minimum and pray you can find enough fuel to do it. You are not going to be able to tell them how to cure up the pork chops or ham or such over the phone. And you should figure on making the distance you are, on foot, with what you have and can find on the way.
More specific, you should have stuff stored for a while for them, and GHB in the truck with you. I realize that this whole idea and my telling can be scary and you should start with stores for a hurricane hitting you and no power for a long weekend. What would you need? What do you have? A nickel says your wife probably could make do with whats in the cabinet for that weekend. Keep in mind toilet paper and feminine supplies would be like gold.
After you are comfortable with that, look to a direct hit from a Cat 3-4. No power for a week, damage to streets and road and no going out anywhere for that time either. Keep in mind your age. Toilet paper and feminine supplies would be like gold.
I anticipate and look at the future from an EMP status. That is the Electro-Magnetic Pulse that basically will shut off whatever runs on or needs electricity to operate. A diesel truck likely will also because of the pollution control stuff on it. Most any vehicle, or about anything else, made after the mid 80s will also be non-operational. Hope you got good boots.
Basically what you have is what you got or what the govt decides to share with you if you follow their orders.
Nemo