If a person is unable to consume or keep down food and fluids they must be given liquids directly into their bloodstream and liquid nutrition needs to be put directly into their stomach through a feeding tube to keep them alive. This isn’t food and drink in the way that we normally experience it.
Hospice workers report that when a person is dying, their organs shut down, and they stop feeling hungry or thirsty. Until that time, what makes a person feel thirsty is having a dry mouth, which is remedied by ice chips or other water in the mouth. IV liquid won’t prevent thirst and people on feed tubes rarely would feel hungry without. But these tools are necessary to keep them alive.
While people often take a black and white approach to these tools, the reality is that people often make different choices about them depending on the circumstances. Most people, if otherwise healthy, would want IV fluid if they became dehydrated due to flu or other illness. Many would want both fluids and nutrition if they were in a coma that was potentially reversible at least for a few weeks to see if they would regain consciousness. Most of my clients indicate that they wouldn't want to be kept alive for years through these tools if they were in a permanent conscious condition. But even if the choice changes from condition to condition, I think it is helpful if the agent understand the choice is to prolong life or not prolong life and not a choice of leaving a patient thirsty or starving as they die.