his defense is that he took shrooms 48 hours before the flight in question and was just trying to wake himself up from a bad dream?

that doesn't pass the sniff test. i'm not aware of any dosage of psilocybin that could reasonably be expected to have effects that last that long. psychedelic effects wrap up within the first 6-12 hours and although the aftereffects (the 'hangover') can have a tail of a day or two, they wouldn't explain such radical behavior.