Rescue! Vandas roots black and leafs drop

[Blueszz]

I'm afraid there isn't much you can do. I succesfully stopped it once in Vanda (Trudelia) cristata but it was has just begun. I removed the leaf, scratched away soft/hard brown spots and covered the wound I left with cinamon (it helps it dry out). The waiting began from that point and now 1.5 years later the plant is growing well, didn't lose leafs anymore, didn't develop leaf loss... putting out lots of new roots, also above that critical point.
You could try the same but I've seen pictures from Vanda's that were decapitated for that reason and the rot was wide spread in the stem. The inner from the stems looked brown but still felt hard to the touch.
A drastic method would be decapitating it and try to reroot the healthy top part... if you succeed in this at all.
I'm sorry, wish I had better news for you.