How about a little fluid?
Comment: If the patient was totally unconscious, instead of being unable to move or otherwise respond to stimuli, so that the diagnosis of coma was correct, then she could not hear. But I would not take that chance.
Question: I wonder, is there any way the people in charge of her care might learn about other remedies and techniques to reduce thirst, so that they do not unnecessarily prolong the process for other patients? Sometimes, even professional caregivers, make decisions that are easier for them, which are not necessarily easier for the patient. It helps if those who know the patient can speak for him or her. Ideally, it would be best if the patient, when conscious, had been clear. My Proxy Directive states: Even if I look thirsty, or I move my head toward water or a spray or mist, please just treat the symptom of thirst, do NOT give me more fluids. I want my competent mind now overrules my primitive not competent mind later.