Agree, Star, IF the driver said he was going to drive home - something we don't know, in this case. (He may have wanted someone to relieve him of the load, until he felt able to drive....)
The problem is, how does one know whether they're seriously ill, or just feeling like crap? The two can feel very similar, you know? There's also the reluctance many feel to admit they ARE sick. Not too many years ago, I myself laid on the couch for five days straight, in too much pain to move, able to eat or drink nothing but an occasional sip of ice water, and refused to go the the hospital, because I kept thinking it would get better. I lost a kidney, and am lucky to have got off with just that, because it nearly exploded, and then I would have gone septic, (systemic infection) and people don't generally survive that - but I could NOT believe I was that sick, because I'd never really been sick before. Some of us don't want to look like whiners, right?
If the driver wasn't adamant about being too sick to drive, I could see the dispatcher persuading him to keep going, for one more day. It would be a tough call - but I'd hope that dispatchers would never push (or even nudge) a driver to go beyond what the driver feels capable of doing.