Hi,
I suffer really badly with fatigue (one year after RT and still on HT). It does feel as if I'm never really quite "with it." It can get so bad that I fell asleep while waiting ten minutes for a hospital appointment recently.
I've just begun a cardiac rehab exercise course to help me take more exercise, they say it's one of only ways of combat fatigue.
Hope it works.
Macmillan do free wellbeing courses, might be worth you checking if you could get him on to one of these if they are available.
Steve