The flyers at the grocery store will tell them what's on special so they don't just grab the first thing they see.
Picking up your 'groceries' at the 7-11 can be expensive and unhealthy.
Have them cook alongside you, including safe food handling instructions as you go, like hand washing, counter cleaning, and that the Use By date is more than a whimsical suggestion.
I put together a basic cookbook for mine, though he still called a number of times while we cooked 'together' long distance, asking for 'live' instructions. And that was fun!
I'd prepare and freeze meals to take up when I visited. He got the idea, and re-used those freezer dishes, making more spaghetti sauce or chicken-and-whatever when he cooked and freezing the lefotvers.
If your son isn't motivated to cook, point out to him how impressed the ladies are with a man who knows his way around the kitchen.
