Anne-Marie, I have been going full tilt since just a few months post treatment. I did not have the double whammy like Nelie, so she has a higher mountain to climb most certainly. If a thyroid check is normal, I would recommend exercise. I found early on that the more I moved, the better I felt. I started early pushing myself to walk farther, faster, and soon was running. Working with weights will also build up muscles that have not been used for a while. I truly believe that exercise speeds up the return to a more normal life. Good luck to your son!