If you are gentle and deferential to the youngster, they will let you simply guide their Beak into tepid Water, and they will Drink.
Have a flat Bottom Coffee Cup of Tepid Water, set it in front of them.
Slightly moisten your finger tip pads in it, shake off the drops, gently 'massage' their Beak as an invitation for feed or water, to get them 'Nuzzling'...
Once Nuzzling, even tentatively, keep your finger tip pads on the sides of their Beak, softly grasping it that way, toward the root area, and, guide it into the Water...keeping them on the Beak in that way as they drink.
In their terms, this provides the tactile-feeling-sense of their Parent's Throat, enough anyway, for them to recognise and accept the gesture as one of inviting them to be Fed or Watered, so they will gladly comply.