I don't know why this should happen; upon recovery a physically healthy person will be back to normal. If not, something else has happened very wrong and I would be concerned! But, surely, when one has a high fever (I do get delerious), then, yes! I revert more into a deeper autistic state. When I'm stressed, overwhelmed, not well, or any sort of 'out of equilibrium' I become further away. I think this is what you mean, yes? Even a NT, when having a cold/flu will feel 'disconnected' due mostly to inner ear fluids and the resulting disorientation (your inner ear coordinates your balance, plus having a cold will muffle or alter your senses). Plus, cold/flu medicine does have an effect!
I am prone to getting high fevers when I'm sick and this certainly makes me kind of delirious. I cannot function nearly as well under these circumstances and I must consciously try to act within neurotypical rules (well, somewhat), so this ability would be compromised too.
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The ones who say “You can’t” and “You won’t” are probably the ones scared that you will. - Unknown