That’s not necessarily true. Myself, and several other people I know, have definitely experienced a boost from stimulants, just not in the same wired way neurotypical people get. Sometimes it feels like a weight off your shoulders that in a way almost feels stimulating. At the very least more talkative.
What incentive does the coroner have? They get none of the payout. They don’t play a part in setting the value or bidding either.