When we're out of danger of frost, remove dead and weak branches. Snip a branch you believe is alive, and if the interior is green, your tree could well recover. When it begins to put on new growth, you might give it a diluted application of fish emulsion. I think indoor ficuses are overwatered. Don't water yours until the soil is nearly dry.
Good drainage is important.
This spring, just before the plants begin to put out new growth, cut the plants back to encourage branching. Use a clean, sharp tool, and make your cuts just above leaf buds. If you want to just shape a plant, cut just the tips of the branches, but if you want to rejuvenate it, cut it back considerably. I've seen them cut back to a foot or so, but you can vary the height. In past springs, I have cut old leaves, one at a time, so the beds always looked green and well-groomed.