D phal lost all its leaves - can it be saved??

[Klup]

I’m new to Dendrobium phal care, and have had this small plant for about a year. It’s in a shaded west-facing window and seemed to be doing ok, but as its new cane developed, the leaves on the old canes dried up and fell off the center leaf on the newest cane did the same, so I cut off the dried portion and treated the whole plant with physan 20. Seemed to be doing ok, but just lost its one remaining leaf on the newest cane. The canes aren’t mushy and I can see a couple good looking roots through the pot. It is chilly in the window, but my other D phal that I got at the same time is totally thriving. Help!?!