Just what do you think the insurance company does? There are a bunch of medical professionals on a panel there that decide what procedures should be covered and why. The difference in this case is who pays those people and what their motives and incentives (shareholders and profit) are when making a decision. They're just as much a "death panel" as the people doing the same job in socialised medicine elsewhere.
Oh and yes, you have the right to sue... I just can't see that having any real use if you're looking at a 6 month time scale. Another thing that no doubt comes into play when the insurance company is looking at the
If on the other hand if the insurance company gives carte blanche for whatever treatment is necessary and also has to factor in the cost over the life of the policy of paying for these expensive procedure... end result... premiums go up, just like taxes have to go up, to cover the cost of the government based health care if the system was to provide a similar carte blanche for doctors to treat as they will.
Towards the end of life, whether that be in old age, or as a result of disease or misfortune, everything reasonable should be done to treat the patient, trade offs will have to be made though as resources are limited and medical care is expensive, requiring trained professionals of which there are limited number and physical resources that have to be paid for.
No matter what, difficult decisions will have to be made somewhere along the line... and it astounds me that when it comes to the provision of health and wellbeing, people think these decisions are better made by corporations whose chief motivation is profit.