As a director of a floor, you set the tone on how complaints such as this should be handled. It is not easy, as we all balance the satisfaction surveys and the generally appalling nature of these type of complaints and comments.
All of the ignorant statements aside, there are often patients who do not want to have discussion with anyone regarding their "business". Totally inappropriate way of discussing that with you, however, there are those patients who just don't want to share.
Additionally, is this a mental status that bears watching? Is the patient's pain under control? Is this agitation new or different or needs further investigation?
The only thing you can do is to state to this patient that there are multiple members of your health care team who put the patient's needs first. That to engage them in conversation is from a place of caring, as opposed to getting into one's personal health business.
That you all welcome constructive critics, however, this person is a valued and highly respected member of your team and is a wonderful advocate for patients. And that you ask all of your staff to engage where appropriate to do so.
You don't want to get into a "contest" about the rest of the ignorant statements this patient made to you. Perhaps for that patient, they found ANY general conversation inappropriate. Also a thought to have education for the ancillary staff as to engaging patient's in conversation, that different personalities will either engage back, or if not, how to "bow out gracefully" from a conversation--and how that can assist your nursing staff in the assessment of mental status and agitation, and that you all welcome their input if they notice something amiss. And educate the patients of the same--that on your floor, you encourage niceties and conversation.
To make a complete collaboration of all disciplines is a wonderful way to boost morale all the way around.