My radiation was post surgery. In my case, the cancer had invaded the jawbone, and that necessitated the 40% removal.

I know that radiation does compromise the bone health, occasionally to the point of bone death.

By removing the compromised bone and replacing it with fibula, she should have a viable, healthy jaw again, probably as strong or stronger that it was before. Stronger because they will likely reinforce the jaw with a titanium plate during surgery.

This is done to ensure that the allignment is maintained; after surgery her mouth will open and close properly. Hopefully she'll be able to get rid of the PEG tube afterwards
Wayne