I think a lot of dens are sensitive to copper; be careful using that.
I have two in bloom now that were rootless rescues last year- they'll come back if they can!
I'm not too terribly far geographically from Angela, humid and mostly warm, and frankly will often treat them like she described. The two rescues blooming were just potted up (so I wouldn't lose them frankly) and cared for as any of my others. When the weather started warming they started forming new growths, which formed new roots, and voila their later growths are now blooming size again. The old canes will usually discard all their leaves trying to conserve resources when they're this stressed; don't worry about it just wait for the new growths and their leaves (and roots).
Without knowing where you are or how big this plant is, here's my idea. Pot the plant up in a very well draining media (dens can't stand wet feet). Make sure the bases of the pbulbs are at the surface of the media so the eyes at their bases can develop normally. Drape just a pinch of sphag loosely on the top to help keep a little moisture; when you have growth remove it. Then cut the very bottom off a big (2 liter plus) clear soda bottle, remove the cap, and place it over the plant. Water (just water at this point) once or twice a week until the pot is streaming. Once a day mist the plant. When you water or mist, leave the bottle off the plant for 5 minutes unless yours is a very dry climate- then just leave it off a minute or two and leave the cap on. Do this until you have a new growth that is 1" or more, than you can start leaving the bottle off to harden it off and fertilizing weakly.
One note- very young new growths can develop crown rot fairly easily; when the leaves differentiate they seem to shed water better. Don't get water into a brand new growth.
This is assuming you have an intermediate, phal-type or antelope den. I don't grow the others. those are the most common types in the mass market trade.
Edit to P.S. many dens in mass market places will be in soil- depending on where you got it, it may or may not be severely broken down bark. I think it's a combination of ignorance on the part of the retailers (don't ALL plants grow in soil? Besides the bark looks unnatural!) and possibly figuring (and hoping) that the buyer will treat the plants as cut flowers and discard them when they're done blooming. After all, they don't make as much money off you if the plants live land you don't have to buy new ones.