This is so sad!
I'm inclined to agree with some of the others. If water was collecting in the leaf joints from the mistings, and also not enough to the roots, and they were drying out, then I think you might have gotten rot right where they meet the center. I have a large Phal noid that that started to happen to way back. I started making sure the roots were damp, but not wet, and keeping moisture from where the leaf joins the stem. I have 2 leaves that are o.k.- I think it will be quite a while (if at all) before it recovers. You might want to start over instead. Good luck!