If your chameleon is too weak to climb I would seriously consider taking out everything that he can climb on. I know that some people will disagree with me, and I do understand their position, but what happened with hermie (my vet thinks) was he had MBD, was too weak to climb but tried anyways fell, broke a limb, kept trying to climb, falling, and breaking more bones. Nasty cycle. Hermie had MBD so severely that you could hardly view his fractures on xray film his legs were so lacking in bone density -- they blended in with soft tissues. Hermie was a tough guy and I give him credit -- he's alive because he was too stubborn to give up, and I just kept fightin for him as long as he was willing to fight.
Hermie had casts on all four of his legs. Yes, some of them did heal crookedly (the only real way to prevent that would have been to put pins in them), but he uses them just fine. He has regained his bone density. Really, in order for a fracture to be healed the break needs to be immobilized from one joint before to one joint after the break. This can be accomplished with a cast/splint, or (it takes a lot longer because there is some movement) with strict confinement. If they keep moving (which they will being chameleons) the bones don't get a chance to heal.
It is hard for them to hunt because they can't move well ... he couldn't stalk his prey or anything. Hermie being the fighter that he is coped iwth it by simply opening up his mouth, and we would oblidge and drop wax worms and silk worms into it, and he would chew. we fed apple sauce and baby food by syringe ... he would open his mouth and we would put some in (no, he wasn't just hissing at us, there's a difference

). he received high doses of liquid calcium twice a day also. we also had to syringe feed him water.
Anyways, these are just my thoughts on the matter.
And ps -- to the person who suggested the soak for a possible impaction I have done them before with hermie. Probably stressful for them (make sure that they don't drown!) but successful also, and better than an impaction. I use them on my beardie regularly and it always is VERY effective...