My 88 year old Grandfather has stage 4 jaw bone cancer, it has spread to his Lymph nodes and his lungs, we also believe up to his brain. He is showiing signs of dementia and has only eaten a couple bites of food today and yesterday, he is not drinking very much fluids. He is sleeping a lot and very difficult to wake up. What would say hiss life expectancy would be? The Dr's are kind of dancing around this question and we really need to know, he has 3 children out of state that we need to let know