From what I have been told about Hermie, it is possible for them to gain their bone density back given the right care and medication. Currently he is on calcium gluconide (sp?) every 12 hours, and we are considering calcitonin to almost completely stop the body's ability to pull calcium out of the bones. But even though he can gain his bone density back, it is likely that his bones will still heal crocked because we didn't put pins in his legs.
Hermie today began hunting down his own silk worms, and I think that I have seen a lot of improvement with him -- his bones are very slowly starting to knit back together and he is becoming stronger and climbing around some more.
Hermie didn't have a soft jaw yet, but he did end up with four broken legs. It happened to him right after I put him into his new "big boy" cage also. Now we have all climbing things removed and him in a 20 gallon aquarium with blankets and now some plastic green plants on the bottom for him to "hide" in. Herm's legs hardly showed up on xray two weeks ago, but it hadn't yet affected his spinal column.
It looks to me like your chameleon's leg(s) are broken. If you want to try to save him I would suggest taking away anything that he can climb on -- it will just make him more likely to fall and break more legs and cause more damage, bc he is likely to fall off.
Every case and chameleon is different and should be treated as such. For us, Hermie wanted to keep living in my opinion -- he kept asking for food by opening his mouth and letting us drop wax and silk worms in -- if he had wanted to die all that he had to do was stop eating and I would have put him down. In fact when I took him to the vet I had every intention of putting him out of his misery, but they were the ones that thought that we could save him.
It's hard to know how reptiles feel pain. To a human broken bones would mean pain, but they don't really know if pain reception is the same in reptiles. Hermie didn't act like he was in very much pain, but the vets put him on pain medication for a week also.
Good luck