PLEASE HELP- How long does he have???

My Grandfather was diagnosed with Alzheimers about 8 years ago. Medication has helped slow the progression, but I feel as though this is it. He is completely bedridden (well in his recliner, he can't sleep laying in the bed). He is unable to walk at all, he refuses to eat all together besides a piece of toast once in a while, he is incontinent with both urine and stool, he doesn't recognize a lot of his family, and he sleeps all day long. If he's not sleeping, he's crying. Even though he is completely immobile, he sometimes forgets and will drag himself out of the chair, and fall, often hitting his head or getting stuck on the floor, where he then either urinates or defecates. Two days ago he fell out of his chair, and now it's like there's nothing there, even though there was no major damage. He doesn't understand anything and is completely unaware of his surroundings. He's still refusing to eat, has zero bodily excretion control, and cries to communicate. He's obviously stage 7, but do you think this is the end?

[Finallyananswer]

I should add he's 85 and has had congestive heart failure.