m certainly not an expert) Lupus
is not always easy to diagnose. Some people with Lupus
will not test positive on an ANA test, so if that's all he did, that really doesn't prove anything.
Also, from what I've read, ypu may get different test results at different points, so you may need to be tested several times before showing up positive for am autoimmune disease.
The really dry throat sounds like it could be Sjögren's syndrome, which has similar symptoms to Lupus.