Yes, I don’t want my dog to suffer. She actually seems fine 90 percent of the time, and does not seem to have pain; no panting, no whining, she does tremble a lot, though.
I would say let the dog go eventually on your terms. They’re always loyal to us, and they trust us; dogs will give their lives to save their masters from things like fires, enemies, and so forth. The hardest part about owning a dog is knowing we will outlive them. But I can’t decide for you.
I’m so sorry about your friends and pets. I’m not a veterinarian, but I think the trembling may indicate pain. I have watched two people waiting, trying to stay alive until a loved on arrived on their flight. Though they were in tremendous pain, the held on by sheer will power. All through their waits, they trembled. I am crying as I write this. Please understand your pets loved you—I ask you not to let them go through pain because of indecision.