How To Treat Adenocystic Carcinoma?

My dad was diagnosed with Adenocystic carcinoma on April 28, 2011. He has decided not to do any treatment since he has had the tumor for well over five years and it can not be removed. In April, the tumor was in the eye cavity, touching the brain in three places, and surrounding his cerebral cortex. I am trying to find out what to expect as far as end stage signs. My dad has lost movement of both sides of his face. He is impulsive one minute, and forgetful/confused the next. One eye is bulging further out. He complains that he can not hear as well and within the last two weeks has lost his ability to speak clearly. He is coughing and clearing his throat constantly. The head pain has returned. My dad s world is closing in on him. How much longer does he have to suffer?