I think the real issue here is not how sick the patient is. it was the bedside manner and the lecturing in a rude way.
The patient may not have been deathly ill, but he was probably scared as to what was wrong with him.
If he was not that sick, you hurry him out and keep your yapper shut.
My MIL was hospitalized for something pretty minor, and was making a fuss. Big fuss. Nurse told her to shut up, people were actually in real pain/ dying. ( Go, Nurse!!)
That nurse got reamed when MIL complained. The nurse was not wrong, but perhaps should not have said this out loud.