Hello Kim
Welcome to the site. You will find so much help and support here in your role as caregiver for your uncle. I can't help with tongue or jaw surgery questions but others can.
As far as radiation goes, patients seem to have various experiences. My radiation was drama-free. I focused all my positive energy on each days treatment, used visualisation during the treatment, rested, slept and generally obeyed doctors recommendations. I couldn't and didn't want to talk much.
Please let us know how your uncle progresses, love from Helen