Umm. He can check out and go home. The end would be quick at that point. No one is forcing him to stay in hospital and get treatment as long as a living will or power of attorney has been completed.
The problem with "government" allowing assisted suicide is that governments rapidly move to enforced suicide to deal with expensive treatments or those political undesirables with "life not worthy of living". Every time the state has been given the power to kill it uses it.