What a sad story. TBDs are so strange. I usually recommend that people have their dogs checked for them if they are showing strange symptoms, or symptoms that don't make sense.
Bridge angel Phoenix was getting very tired during walks, to the point where he could barely make it across the street without resting. I took him to my vet, who had no idea what could be going. I remembered hearing about a vet 40 minutes away that a local adoption group used to test for TBDs. I took Phoenix in for testing, and sure enough, he has babesia. I called my vet, who made some comment about stupid American dogs (I live in Canada) bringing their diseases across the border. Needless to say, I changed vets and he was treated with imidocard, which had to be imported from the United States. It is a very painful shot that can have nasty side effects. Treatment began after the vet saw the nasty critters in a telescope.
My point is that lots of vets, especially in Canada, may not be aware of some tick diseases. Babesia is caused by the brown tick, which doesn't even live in Canada. Be vigilant for your dog.