That is so sad! When we first brought Jaws home Spike attacked her and almost ripped her tail off. I took her to the vet, but they couldn't stitch it up, they said that it had to heal from the inside out. I had to clean it everyday and then put this ointment on it. Before she got hurt, Jaws would let you pick her up and she loved her daily swims (in the tub). After she got hurt she wouldn't let anyone touch her. I think that she decided humans cause you pain, and even though it's been more than 13 years or so, she still won't let you touch her.
Iguanas average life span is 15 years. Mine are both vegetarians and have never had meat, so they will live a little longer, but I don't know how long.
Here's a link to the pix I posted: