That would be a hell of a twist, but it would also feel somewhat dishonest. If it was a storyline, presenting it internally as PTSD style flashbacks is sort of lying to us as the audience. If he's actually making them suffer PTSD and letting them react accordingly, it might work better as a twist, but then I've lost reason to care about the Hosts if it's just being faked.
If you can't tell, does it matter?