Root rot

The roots look ok to me, just pot your phal? in fresh compost (not too big a pot) give it a good soaking, make sure you don't place it in direct sunlight. Good luck.

 

I assume that what you have there is "what's left" of the root system, which has probably succumbed to suffocation in an old, overly-compact potting medium.

Personally, I'd soak that plant in a good root-growth stimulant and pot it up in fresh medium. Then, invert a clear plastic bag over the plant and pot to trap the humidity, and place it in a very warm, deeply shaded location.