I know I'm a little late but this forum was just brought to my attention. This iguana does have a chance if you're willing to put in the effort and it's willing to survive. Most iguanas have a very strong will. Here are a couple of photos of bad cases that we've had come into the rescue.
Wizard was 3 years old when he came to us and the size of a yearling. He had one of the worst cases of MBD that I've ever seen. He had multiple fractures in his legs, curvature of the spine, and his jaw was horribly disfigured. With good UVB (ZooMed PowerSun), CA supplementation, and a good diet, he has recovered well and is doing just fine. He's even grown 6 inches in length!!
Lumpy came to us as an adult, supposedly with an ill temper. He has a very strange deformity of one eye....it bulges way out and is huge! Ultrasound shows an old abscess or cyst behind the eye and multiple old fractures of the bones in the face. He also has a terribly undershot lower jaw. He has filled out under our care and is a sweetie. He's a very dependable tolerant educational animal for us.
Please do what you can for your new iguana and you will be rewarded in so many ways. Best of luck!