Willywee,
I'm no longer editor here but found your post to me while doing a search for a thyroid article. I'm always glad to reply to any questions I'm asked. By now your son has already had his appointment.
Symptoms are the same for both men and women with exception of how thyroid problems affect women's menstrual cycles.
In my opinion, doctors should order "thyroid antibodies" to be tested when evaluation a person's thyroid, Antibodies cause the diseases that eventually cause thyroid hormone imbalances. Symptoms can begin in advance of hypothyroidism or hyperthyroidism showing up in the lab hormone levels.
Some doctors claim symptoms will not show up before thyroid hormone levels are out of the normal range but goiters for example often appear as a symptom with lab results for hormone levels still being normal. Medical research concludes in many articles on PubMed and other reputable sources, that emotional symptoms and rheumatic ones (joint/muscle) can also start before hormone imbalance is detected.
If his doctor rules out thyroid imbalance, a disease that can be working in his body despite this should also be ruled out by testing for "anti-TPO" and "anti-TG" antibodies and "TSI" antibodies if he is experiencing hyperthyroid symptoms. It's possible his vist already revealed something and if that's the case the antibodies tests, if not already done would be more of an option and only a way to determine "cause" of the thyroid imbalance.
If his doctor will not add these tests for better evaluation and all other testing was normal, you can order them through a firm like HealthCheckUSA.com without the need of a new doctor visit.
Best wishes with it and I'll check back to see how it goes with his evaluation, if you can update.