MBD dragons are sometimes crippled by the disease. It's because their bones soften because they're lacking calcium and their bodies robe it from their bones. There are BD's with serious MBD who live happily after they've been taken care of and given the proper calcium and UVB lighting. You need the
UVB light, because without it he's not processing any of the calcium. I hope you can get ahold of the proper light. The coils don't emit enough UVB for a BD, so he's probably not gaining any calcium from the dusting. Keep dusting though, in case that little coil you have helps him process even the slightest bit of calcium.
Just as I expected, he's dehydrated. Give him 2 baths a day if you can, so that he can absorb more water through is vent and possibly even drink some more. When they drink the water by mouth themselves, that means they're severely dehydrated. Now that's not your fault, so don't get mad at yourself. Try spritzing the veggies with some water as well to get some extra water into him.
Hydrated beardies are able to function properly.
The MBD is most likely causing the shaking. His legs are weak because of the disease so he probably cannot fully hold himself up. Now I don't know if he'll ever be able to walk properly again, occasionally an MBD who is given calcium/good UVB can regain some strength. Did you mention his jaw being unaligned? Like the bottom juts out further than the top lip? That will most likely never realign, which is no big deal. He may not have the most "fancy" jaw, but he's a real trooper and looks don't matter as long as he's healthy.
I'm so happy you took him in and are trying your best to help him. Please do give yourself a pat on the back and feel good about what you're doing.