How long will a terminally ill patient live without hydration or food while sedated?

My father in-law is currently dying from cancer. He's on 2 automatic morphein pumps & "medaz" sedation every 1-2hrs. He has had no fluids, of any kind, for 12days (no food for 13days). He was "bleeding out" quite heavily from his nose & mouth last week & we thought it was the end, but he's still here. The whole family has put their lives on hold, thinking "today is the day" but after 12 days of thinking it, we dont know what to do. So the theory of surviving without water for only 3 days has been blown out of the water by him :(