I'm in the same boat as you Denis. I bought 2 Phals that were on sale because they had finished flowering. Both looked very healthy when I bought them. Since then, I noticed that one of them was drooping badly so I took a close look and noticed it had mealy bugs. I solved that problem but it didn't do any better so I repotted. It was then I noticed that the pot it had been in, still had the holes sealed, no one had bothered to punch them out! When I took it out of its pot, I noticed that the roots were mostly rotted. I cut most of them away but amazingly the plant is setting buds. I finished repotting and am now hoping it survives. Think it will stay alive? I will be following this thread to see what advice you get. Marg

I got to tell you that I don't think that fella looks too good. I am not a big fan of bringing plants like that back to life myself. But usually when a phal is missing the more recent leaves it is a goner.It barely has any roots either to support it.
You could bag it in some sphagnum moss and see how it goes...

My opinion is strictly anecdotal but I think that it will pull through. It is a matter of patience because I am sure it is going to take some time for it to recover (of course assuming it recovers). I purchased a sad little phal like that a while ago. It took almost 18 months for it to recover fully. It sent out a flower spike about a year after I got it but I had to cut it back because it was taking too much energy from the plant. However my sad little phal is much happier now. It just took a looong time.