Every part of the coconut can be used in one way or another.
The trunk and leaf stems of the coconut are used for building; the leaves themselves are woven into baskets and mats; the fibers around the nut make 'coir' for doormats; the milk-juice inside the unripe nut makes a refreshing drink. As the nut ripens, the milk turns into the white flesh within the coconut and this, in turn, can be dried to make 'copra' which can be pressed to produce coconut oils for margarines and soaps, with the remnants being used for cattle feeds and fertilizers.
The natives also obtain a juice from the flowers of the coconut. This can be made into a fermented drink which they call 'toddy'.
There was a recent television series called Off The Map, with young American doctors working in South America. They used coconut "water" (the unmature milk of the coconut) as an electrolyte replacement.