I had a family member who wasn't even in ICU, and still experienced delusions simply from being sick and being in the hospital for a few days. He thought there

I had a family member who wasn't even in ICU, and still experienced delusions simply from being sick and being in the hospital for a few days. He thought there was a group of family members around the corner waiting to jump out and surprise him and was insistent that I tell them not to disturb the other patients. I had to argue with him to get him to accept that, no, there is not a random group of family members waiting to jump out. He insisted he heard them talking and stuff. It was pretty disconcerting for me actually because he has always been a psychologically-bulletproof person. Definitely an eye-opening moment for me.