Patty, if you want to give it some strength in recovering, use a mild solution of Alaska fish emulsion and foliar feed it on the leaves and the trunk. From my experience, a plant in such a condition will take 4 - 8 wks to recover. DON"T WORRY......
As the new leaf comes up, continue the foliar feed. As it gets better, increase the strength of the solution. This way, you allow the roots to come on without getting burnt by any fert which most people apply to the soil.
For my smaller plants, I use a clear plastic bag to cover it completely to retain the humidity and it helps the plant to recover faster. To make you feel better, just last week I screwed up a pretty rare
Callimusa and I used this method, and it has stabilized.I caught it fast enough so I was able to arrest it. I think it's the only plant in cultivation anywhere. I felt bad cos of my negligence but I was lucky to spot it as the leaves started a slight droop. The first time this happened to me was my 2ft p-stem Helen's Hybrid. I thought the droop was from the heat wave as it comes from a cooler country. I let it be for 2 weeks until it looked real bad. At that same time, stupid me was over confident and added a strong fert after repotting. I had to take it out and change all the soil and then repot. It took 2 bloody mths for it to come around. Your plant is big and have been vigorous in growth so it should make it.