If you all go in there, and your other dog witnesses her death, on the vet's table, it is just possible it might make HIM afraid in
going to the vet. Dogs
are no way stupid. They know going in
there they smell sickness, and nervousness, which is bad enough. They can't put two-and-two together quite the way we can. They can't think "our loved one was sick, so we went to the vet for her suffering to be ended" All he will observe is her death while at the vet's.