If it were mine, I would repot. It would give you a chance to see what is going on with the roots, get rid of all the dead ones and replace the media.
I would treat it as if the roots were also an issue. What works for me is to repot in spag, because it's easy to kind of poke around and check out the roots for those nice growing tips. If you leave a loose top layer, you can lift and peak to keep checking.
I'd also lower the light and up the humidity. The plant has obviously been stressed, but with the new growth on the top, the roots should be growing and should establish in the new media quickly.
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