I wouldn't trust Harry to know the difference between unconscious (or faking it) and dead.
"Or faking it" -- indeed. The most damning bit seems to be:
something in the depths of the dark pair seemed to vanish, leaving them fixed, blank, and empty
but three pages prior there is something almost the same, where Snape is clearly still alive:
Snape’s face was like a death mask. It was marble white and so still that when he spoke, it was a shock to see that anyone lived behind the blank eyes.
no subject
"Or faking it" -- indeed. The most damning bit seems to be:
something in the depths of the dark pair seemed to vanish, leaving them fixed, blank, and empty
but three pages prior there is something almost the same, where Snape is clearly still alive:
Snape’s face was like a death mask. It was marble white and so still that when he spoke, it was a shock to see that anyone lived behind the blank eyes.
So hey, it could happen.