David,

That appears to be rot. I hate to say so, but I don't have high hopes for
the plant, with all that necrotic tissue. What you can try is peroxide,
sprayed all over the plant, and watered through the medium. Also, it
appears that the parts of the leaves nearest the crown are not so badly
affected yet, so you can try cutting back to good tissue (using a sterile
blade) and then making a paste of Elmer's glue and cinnamon to be applied to
the cut edges of the leaves.

Can I assume that you are growing the plant shady and out of possible rain
fall? Phals need to be watered in the morning, so that they have time for
the leaves to dry before nightfall. And, it's important to keep water out
of the crown. Watering every few days, with our humid weather down here at
the moment, might be too much, but I can't say that for sure.

Hey. If you lose it, you lose it. Go get another!

Diana