It looks as if it is always crying. It is actually adjusting its body’s fluid levels by eliminating excess.
When this Pokémon is at full HP, any hit that would knock it out will instead leave it with 1 HP. Regardless of its current HP, it is also immune to the one-hit KO moves: fissure, guillotine, horn drill, and sheer cold. If this Pokémon is holding a focus sash, this ability takes precedence and the item will not be consumed.