I believe 100% in the powers of meditation, but this is out to lunch! Even just by breathing your body is releasing moisture, so you would have to have some water intake. Maybe his cave is so extremely damp that water collects in his nose and gives him this drip?!? Only thing is he would still need electrolytes, protein, etc. just to continue to have a beating heart.
That said I have done fasts from 2-5 days (not the type where you're allowed to eat at night, but a true fast) with either juice, water or water and unsweetened green tea. The water fast with green tea each night was my favorite fast. It lasted for 4 days and I came out of it by drinking about one cup or juice on the 5th day, a few on the 6th, and back to whole food by the 7th day. It's amazing how much more energy you have, and less sleep you need, when you're not spending time digesting.
We eat ourselves sick!