Just reading posts I have missed while being off line.
So sorry about your loss. Having kept goats for many years, believe me, I have been in your situation numerous times. Back and forth to the vet with a goat who is not right, but nothing you can put your finger on,. Our vet admitted they find goats and sheep hard to treat, goats especially as nothing is licenced.
Sometimes, you go into the shed next morning, dreading what you will find, and there they are chewing the cud, perfectly fine ......
Its such a shame but you did all you could