People say there are five stages of processing grief: Denial, Anger, Bargaining, Depression and Acceptance. Ashton's case wasn't different. The stage of denial passed as quickly as it had appeared.
Now, was rage's turned. All sense of reason and logic had long since left Ashton's mind. Was he being discrete? What was the point of it now that he found his father in such a pitiful state?
The sole purpose he wanted things to be quiet was to ensure he could get his father out of there had he been alive. In a way, his father was alive, but Ashton wasn't deluded enough to think the creature in front of him was his father.
The thing might have shared a resemblance with John, but it was no longer him. His body was only the shell, storing the soul of a monster within... at least, that was what Ashton kept telling himself; otherwise, he won't be able to do what needed to be done.
'Astaroth, is there any way to turn him back?'
[... I'm afraid not.]