If it widely know that this incurable disease is incurable then no doctor would risk his professional name by claiming such a thing, and no it would not be "malpractice".
It all depends on damages. If there is an incurable disease in play, liability is by necessity, limited, by the simple fact that a bad outcome is inevitable.
It all depends on damages. If there is an incurable disease in play, liability is by necessity, limited, by the simple fact that a bad outcome is inevitable.
That's all you Americans care about - suing for money.