My grandfather is on palliative care now with cancer.

we know he is nearing the end as he has stopped eating and only drinks when he has to take a tablet or for a taste in his mouth. 
He hasn't pee'd in over 24 hours now although he lost control of his bowels earlier today :(.

he sleeps most of the time but is very much there and alert when he is awake. 

By the sounds of all this and with others having similar experiences... how long do yous think he has ? He hasn't ate in over a week. 

Thanks x