It took me 10-11 years to get diagnosed with CFS/CFIDS. Find a good doctor that will listen.
My diagnosis came after TONS of tests. I had blood work for just about everything you can think of, had to see a sleep specialist to rule out sleeping disorders... then found a doctor that ran a test that no one else had ran... for the Epstein Barr Virus, and came back positive... and I got my diagnosis. My white cell count was also a little elevated, but there was no evidence of any infection... etc.
While it is very possible he may have CFS, like was said before there's many other possible causes. Unfortunately, there's no test to run for CFS, you have to rule everything else out first.
Good luck with everything,... and just remember he may need your support.
I have chronic fatigue syndrome, anxiety (at this current moment), and some minor abdominal pain which still hasn't been figured out yet... need a break from all the testing ;)
CFS: Provigil 200mg, once a day
Anxiety: Lorazepam .5 or 1mg 3xs a day or as needed