I worked as a transplant coordinator for a few years, and you're mostly right, but there qre a few points I would clarify.

Dead is dead. All transplants are post death.

All of your organs need oxygen to keep functioning. When they don't have oxygen, the cells die and the organ stops working, but you can be dead and have functioning organs.

When your brain is deprived of oxygen, the neurons stop firing and you're gone. Dead is the irreversible cessation of brain activity. Sometimes organs can heal, but once your brain is gone, you're dead.

Sometimes that happens because your heart stops beating. The muscle in your heart can also die, and it will stop pumping blood. This heart failure deprives your brain of blood, and then you die. When your heart is failing, you can stimulate the heart to keep beating and continue to live. But if your heart stops beating and you die, that is called a cardiovascular death.

You may also lose oxygen due to a failure of the lungs. Lungs put oxygen in your blood, and if your lungs fail, you don't get oxygen to your brain and you die. This could be related to the lungs, the vasculature between the heart and lungs, or any combination of the three.

The liver and the kidneys work to filter the blood. If either of these fail, your blood can become toxic and poison your heart, your lungs, and/or your brain. The liver and kidneys also need oxygen to live, so if your heart stops beating or your lungs stop providing oxygen, then they will begin to die at the same time as your heart.

Like your organs, your muscles, skin, and nerves also need oxygen to live, and if you have trouble getting oxygen to your peripheral systems, your limbs can begin to die and become necrotic. Necrotic tissue creates a feedback loop of decay in your blood stream, and often requires amputation.

Covid affects both the lungs and the heart. Lung damage reduces oxygen in the blood, and heart failure reduces the flow of blood to the extremities.

Now, in the event of a traumatic brain injury, like a motorcycle accident, the brain can be killed before the other organs begin to die. The heart has a special mechanism that allows it to continue beating without input from the brain. These are ideal circumstances for organ donation, because the donor has died but their transplantable organs are in good condition.

It might be different in other countries, but in the USA, there is a network of transplant professionals that work together to procure and distribute transplants. They work with the hospitals to identify potential donors and talk to the families about donation options.

The hospital would call the local organ procurement organization every time any patient had a traumatic brain injury, even before they died. Patients would continue to receive treatment in the same area of the hospital by the same doctors and nurses. There is no "donor ward" and the only difference in treatment is that additional efforts will be made to keep the transplantable organs alive.

The patient's doctor wants to keep their brain alive along with everything else, and they only stop trying when it becomes impossible to succeed.

So, while I'm sure that your friend really did experience the loss of a limb, and I'm certain the OPO had dispatched a transplant coordinator to evaluate your friend for donation, there's no way the family was approached for possible donation without a dire prognosis (or maybe they asked). The approach would have been in the same conversation where they discuss withdrawing care because there is no hope.

The doctors and the family may have mentioned that they had discussed donation to demonstrate how dire the situation seemed, and how close to death your friend was, but they would not have altered his care at all or moved him to a special section for donors.