You and Holly are in my prayers. I, too, had an oldster who was tiny - not as tiny as Holly (he was 12 pounds) but really small nonetheless. My Neechee was 17 when he went to Rainbow Bridge.
I had a similar problem when Neechee had a stroke when he was 15. I was recovering from surgery, and he and I were lying on the bed taking a nap. I woke up an hour later, and he couldn't stand up at all. Went immediately to my regular vet, who said it was time to put him down. I couldn't see that because he wasn't in pain.
I called my groomer and she told me to see Dr. Eric. He immediately told me Neechee wasn't in pain, put him on Valium and steroids but told me that he might not live through the weekend. My instinct said not to give up, and I spent the weekend by his side, as he got really agitated when he couldn't see me.
He WALKED into the vet on Monday morning, a bit wobbly, but fiesty as ever,
My point is that you should go with your feelings. If your gut tells you to go to another vet, by all means find another vet. If you have the time, call around to different practices and see if you can find someone who treats a lot of geriatric patients. They will usually be a lot more creative in finding ways to extend the life of your dog.
My best to you and your Holly. Caring for these precious oldsters is both a heartache and a joy. I will always be grateful that I was able to spend so much time with Neechee - and that last year, took him everywhere with me, including church.