"The trick is to harvest the organs before the person’s heart slows so much that the organs begin shutting down and are unusable. If the patient dies quickly—doctors say within 20 minutes—the organs are still good and can usually be transplanted. This year, doctors in Denver managed to do just that, recovering organs from a patient who wasn’t brain dead but whose family decided to unplug a ventilator…. More than 1,300 people in Colorado are awaiting transplants—a demand critical enough that patients, surgeons, and medical ethicists are beginning to question the brain-death criterion and wonder whether something more liberal may be appropriate. But those doing the diagnoses say redefining the point at which death occurs is a slippery ethical issue—one that may have a reverse effect on organ donations because of fears that the practice is predatory."
https://www.crisismagazine.com/vault/how-science-is-redefining-death
Something to keep in mind...they don't use anesthesia when harvesting organs.
That means, while you may or may not be brain dead, your body is going to feel the pain of harvesting until you expire.