Sorry to hear that LMPG
little Cobalt.
I had the same kind of experience with my tabby Tinka 15 years ago, didn't spend $2,000 but $950, so in today's dollars not far off, same thing test after test in the meantime poor Tinka was just wasting away, when the Vet suggested more tests to see "if", I said no...I couldn't handle seeing him suffer any longer.