Yes the suggestions in books will help but will not cure. I am glad you will be seeing a vet. Basically the vaseline suffocates the living mites but leaves behind all their eggs to hatch. The eggs hatch so quickly and they reproduce so quickly that even by using daily treatments of the vaseline it is just a delay tactic. The bird will look better and be fine for a short time but the eggs will just keep hatching, producing more eggs etc until a real cure is used.

I am glad your bird is doing better though and look forward to hearing an update after a vet is seen