That's true, and very helpful for family members to understand. They're also often in a suggestible state. But it's not just full-on delirium; as others have

That's true, and very helpful for family members to understand. They're also often in a suggestible state. But it's not just full-on delirium; as others have noted, in the elderly even infections can trigger wishful escapades (even as the elderly fail to mount much fever). And the question remains: how to help the person (delirious or not), particularly when drugs are not effective (and you don't want to drug them into a stupor). It seems unhelpful to agitate them by arguing with them, even if the reality principle is normally the saner option. Do you "go with it"? My take is that it does help to respond so they know you're there, and really helps to rub feet or back, because body sensation is grounding. But mostly notice how driven you feel to help, or to get involved with managing other helpers, and be very patient with that. Telling the family it's enough for them to be there is often the best thing.