Scooby Doo mourns!
A ventilator is “life support.”
Food and water are not “life support.”
They are basic human rights, not medical interventions that can be arbitrarily withheld. Withholding them will cause his death, not the dementia or the sepsis.
If his body truly cannot assimilate them, then yes, they may do more harm than good. But that is rarely if ever the case these days in stories like this.
And Batman’s sidekick Robin.