For the most part, I'd say that's a goner, but there does appear to be a small amount of viable mass (mostly those aerial roots), so if there is significant sentimental value to it, it might be worth at least trying to save it.
Basically, by letting it remain in the same decomposing and compacting medium for so long, especially in what was likely a poorly-draining pot, you have suffocated and killed the roots, giving the plant virtually no way to take up water, hence the extreme desiccation.
Unlike terrestrial plants, epiphytic orchids do much of their gas exchange processes through their roots, rather than through their leaves. The key to success with them in understanding the balance required between air and water in the potting medium.
If you do want to give it a try, I can recommend the following:
- Buy a bottle of Kelpak Biostimulant and mix up one ounce in a gallon of tepid water.
- Immerse the plant in that for a couple of hours.
- Pot it up in a good, fresh potting medium and container with reasonable drainage, then water it in with that solution.
- Invert a clear plastic bag over the plant and pot, leaving it unsealed at the bottom.
- Move it some place very warm and shady. 100? is not too warm; 75? is marginal, in this case.
- Over the next several weeks, keep the potting medium moist (never soppy) with that same Kelpak solution.
If it survives, you should see some new growth in about 6 weeks, and once you see roots entering the potting medium, you can remove the bag and treat it normally.