Your friend can not and will not receive a transplant if he continues to drink. I'm unsure of his mind-frame or commitment to sobriety, but his doctors will know if he continues. I will tell you that from a Healthcare perspective liver failure is not easy or pretty to watch someone go through. Try to be there for him as much as you can, do not be surprised if he doesn't seem able to grasp the complete scope of his problems because when your liver starts to fail you have more and more toxins in your blood which confuses the patient, irritates the patient and can at times cause them to become violent.
There is no ethical problem here, we as a nation take care of these people and could have possible helped him sooner if we had a better mental heath system. Hope this helps and best of luck to your friend.
PS. He may not need AA for recovery. The threat of death may be all the motivation he needs.