A virus lasts a week to 10 days. If this child has been sick for 2 weeks, then he probably caught one virus on top of another due to a low immune system, poor guy. It does suck, but it happens all the time. Vomit on the other hand or diarrhea means exclusion from daycare, I don't care the reason. Don't be afraid to enforce that rule. Green mucous can mean bacterial infection so ears, throat, chest can all be in danger. I agree that you should be asking the parents to get it checked by a doctor.