Forgot to Change Site

I dropped him off at work and a couple hours later I get a call saying he forgot to change his site this morning.  He had about 2 units left so that gave him a little more than 2 hours and he could not eat anything with carbs in the meantime.  He is at risk of getting DKA (diabetic ketoacidosis) within hours of no insulin delivery.  Thankfully, I was at home & we live very close to his work so I packed up the site, the wipes, the cartridge, the insulin, and the tegaderm and delivered it to him.  

Not too long ago, we lived over 25 miles away from his job and did not have a car, what would of happened then?  I worry myself so much.