Man, that is just the worst thing!
Apart from being run over by a car, it is the worst thing that can happen to a dog.
I don't quite know how to express this in english, but I'm really sorry for your loss. I know how much losing and old canine buddy like that hurts.
I have a good friend, who is a vet ( with 2 dogs and 2 horses, that is a blessing)
He told me that with older dogs or dogs that are not in good physical shape, they don't even try to save them when the stomach turns. The damage is just too great for them to recover.
You have 3/4 of an hour at the most, before the damage from lach of blood supply is to great.
I had it happen to my best dog, the first Thais ( I'm now on the 3rd Thais)
Back then I didn't have a tame vet on call, so I called my pay by the hour vet and was told that I had ½ hour to bring the dog and they'd have a team ready to operate.
I tossed him in the back of the jeep and drove like a madman to Haslev. I made that trip in 18 minutes and honestly, I doubt I could do that on the bike today.
I passed a line of cars by driving in the bicycle lane and went the wrong way round in 2 rondabouts.
As I entered Haslev, Thais stood up and belched mightily.
At the clinic, he jumped out and wlked inside by himself.
Turned out that the mad drive, with the dog rolling around in the back , had returned his stomach.
He suffered badly from damage to the aesophagus for the rest of his life, though, and could only eat small portions.