Ignore sell by dates. Use by dates are the only thing you want to worry about.
Sell by dates are ultra conservative ie they want the food to look pretty when you eat it. If food doesnt look pretty that doesnt mean you cant eat it ie if the can is 10 years old and unopened and covered in dust that doesnt mean you cant eat it, it will probably be fine.
Use by dates are important, ie if you buy a sandwich from a garage with todays date on it then eat it today or throw it out.
shoulda been fine, realistically food poisoning was the worst that could happen which causes major diarrhea, and some throwing up (i got food poisoning while in cambodia)... it sucked A LOT... needed to iv bags to rehydrate me, but im sure if he was improvising a gallon of water would be more than enough. Very light foods... and pretty much wait it out. A fever will probably hit,and you take motrin to get the fever down, then lots of water and you're good.