I think energy levels and depression go hand in hand- I think once the meds kick in he may start to come out of his funk and I agree klo seriously some Drs are amazing - some downright suck. I was the one who told my MO I wanted a tsh baseline prior to rads etc... And she set it up! No one even suggested it! Much like the physio, acupuncture or massage all of which has helped dramatically reduce my post treatment issues. Also I know depression is related to a chemical imbalance - but unless he had a history of depression, or radiation messed with his levels, ( possible) I would lean towards thyroid issues (maybe combined with some of the emotional trauma of having cancer of course) seriously I've seen and known people who's thyroid's are out of whack and it can be devastating. Good luck battling the medical establishment! Hugs!