It sounds very much like bloat, & this was posted at 7:30 last night, Eastern U-S time -
it's now 1-pm of the next day, over 16-hours later. // If it was
bloat, ALWAYS a vet-emergency, which cannot "wait until morning", & he was not taken to the ER, odds are good that he has died, or is alive, but has organ damage - which may or may not be treatable, or even survivable.
Bloat interrupts the flow of blood to the parts of the GI tract that have twisted, & the tissue dies quickly - entire sections of the bowel, esophagus, lower or upper stomach, including the crucial valves at ingress & egress, can die, become necrotic, & send toxins thru-out the body via the bloodstream.
In addition, pressure from the swollen stomach puts a tremendous load on the heart & lungs, & swelling can physically inhibit the diaphragm - making it impossible to breathe. Suffocation & heart failure are both possible.
The LIVER is damaged by the flood of toxins in the blood, & the kidneys are overwhelmed; filtration suffers, & they are likely to go into shock, when the body simply shuts down, unable to maintain homeostasis or even life itself.
I certainly hope I'm wrong, & he didn't bloat - plus, i sincerely hope he was seen by a vet, urgently.
But the prognosis, from the described symptoms, doesn't seem good.