When I had a bad fever (swine flu), I heard voices that were difficult to understand or were confusing. Sometimes I’d hear a voice clearly call my name other times it was just kind of a mumble that didn’t make sense. In my case I just described a hallucination, not a delusion, but sometimes people get the terms confused. My random speculation aside …
delusions lasted more than two weeks during his time both on and off the ventilator.
That’s a long time to be in a poor mental state! 
