Sorry for what you are dealing with . It is never easy .
My rednose made it to 17 . Lost my bluenose unexpectedly at the beginning of covid at just 8 .
That being said , I just wanted to point out how much lower of a humans lowest dose , a dog actually needs. Not even comparable.
My Bluenose once licked a tiny drop of my butter off the kitchen floor before I could stop her once. She was completely fucked for days. Including seizure like stuff early on. She ended up being fine. But just a good example of how little their dose needs to be.
I hope it is successful in bringing some relief to your dog and wish you nothing but the best with it.