With no water, the pills won't matter. Dehydration can't be solved with a pill.
For the sake of this discussion, we'll assume that the pill will solve no water. They'll still die. Why? Wait for it....

















For a pill large enough to have enough to sustain you for all those days, it would have to be a huge pill.
Now how are you going to get that pill down if you have no water?
Like I said, no water, they all die.