I hope the brace offers some relief. I have no idea what an offloading brace looks like, maybe it's a different kind of brace. I wore braces on my knees for a long time, and the last orthopedist I saw told me to shred them. Wrapping my leg in a brace actually didn't make things any better as you have to be careful with surgeries, casts and anything constricting. But my legs had atrophied to such a degree that I could barely stand or walk. He said the braces would allow it to further atrophy (so I don't get the offloading brace at all!). This was after 8 months of PT. I wasn't receiving any treatment for RSD, wasn't diagnosed at that time yet. And this is when the orthopedist told me to ditch the PT as well. I had to do one exercise spread out over the entire day. Did that for 3 years without missing a day (!) just to get some musculature back in my upper legs. My upper legs at that point were thinner than my calves and I barely have calves.

I'd go get a second opinion, third, even fourth on that brace if I were you, and on the state of his RSD. Better you get as much information from a lot of different sources early on!