I totally agree that this is the most frustrating scenario that anyone can face. I think that hospitals and the medical field in general today have become so paranoid about being sued that they are just not willing to actually allow a patient to make their own decisions about their care.
Develop a legal document that allows the patient to sign and be treated as he wishes when there is no glimmer of hope about the outcome. They've treated enough patients to know that once someone is intubated, the odds are you are not going to survive this.