Metaphorically, if something is "on the rocks," it is in a state of severe difficulty and likely to fail soon.
: The ice serves two functions—it chills the spirit and, as it melts, provides a slight dilution that can "open up" the flavors of a whiskey or rum, making it smoother to drink. On the Rocks
In the world of spirits, ordering a drink "on the rocks" means it is served over ice cubes. Metaphorically, if something is "on the rocks," it