I think some people here would say they do have 100% of their energy back. I am two years out and still don't feel that's true for myself, though I have enbough energy to make it through the day, but that could also be an effect of aging, perimenopause or something else. Also, I had two different rad treatments in a year for two different cancers which I think made the getting my energy back thing much harder.

Your son should definitely have his thyroid checked, though, if he has not had it done recently since one of the main symptoms of a failing thyroid is fatigue and it's not at all uncommon for the thyroid to fail after radiation.

A doctor that I saw for help with swallowing problems when I was about 9 months out from radiation (about where your son is now) told me that I should consider myself 70% healed from radiation but that the other 30% could take up to another year--that last little bit of recovery is very gradual. So tell your son there's good reason to believe he's not at his new normal just yet and things can still get better. I hope it cheers him up.

Nelie