If the branches are as brittle as you say, that's not good. See what the nursery has to say. I'm sure others here will have some advice for you too.

My guess is that it is severely root bound and needs to have the roots soaked. Also, it was probably grown in a greenhouse and used to high humidity. You will get a better answer on the houseplant forum, we talk about the edible fig here.

Unless Emily has confirmed there are actually 2 separate plants and not 2 branches masquerading as trunks, which are connected below the soil line, we probably shouldn't take for granted there are 2 plants. Even if there were 2 plants, it doesn't look at all like there would be the kind of competition between plants of the same species such that one would be genetically vigorous enough to hog resources to the point it would create deficiencies sufficient to manifest a steep decline in the other. I mean, there are no roots crawling over the surface of the soil, and there is no disparity in size that could suggest a larger, taller plant might be shading out its shorter, smaller counterpart - so what competition? It's not unusual for one or 2 roots to be negatively affected by disease while other roots in the same pot or even on the same plant are better able to cope with less than ideal soil conditions. The result is often the death or decline of 1 plant in a group planting or one branch on a tree. Roots do have very specific connections to individual branches such that the death of a root can almost automatically mean the death of one branch. The 1 root to 1 branch connection is so strong in Thuja occidentalis (eastern white cedar) that when the center of old trees rot completely away, you can often observe several live veins growing from thick roots, each supporting only 1 branch. Most observers would think they were observing a ring of unusually shaped trees if they came upon this interesting occurrence in nature. Given the volume of soil available for root colonization, I just can't see it being a case of one plant outcompeting another, if in fact there really are 2 different plants. I'm pretty close to certain the issue is related to root health. Al

Direct sunlight would be outside in direct sun. The sun coming through your windows is already going to be filtered light. It would be very good for your tree to repot into a container with drainage, use something like the 5:1:1 mix and place it right up in front of a southern facing window where it recieves as much light as possible. I grow quite a few ficus benjaminas. They have the same general needs as your tree. Naturally, these trees want as much light as possible. Anything that says they don't like direct light is false. It's just that indoor grown leaves can't handle full outdoor sun unless acclimated. In the winter months, I keep the tree in front of a southern facing window with the addition of grow lights. I have five 55w (250w equivalent) 5500k grow lights above the tree. In the summer, I acclimate the tree over a span on a couple weeks and then place it in full direct sun all summer. That is when it puts out the most growth. Literally grows a couple feet every summer. the tree is 7 feet all and was under 4 feet tall when I got it a year and a half ago. Currently in an 18" terra cotta pot in Al's 5:1:1 mix.