I don't see the reason why your son decided to stop eating gluten listed in your posts.

Although gluten sensitivity is "trendy" right now, a real wheat allergy and Celiac Disease can cause very serious problems if it is ignored - especially when recovering from a brain injury!

My Dr. diagnosed me with a Wheat allergy (and a sesame seed allergy) after sustaining a concussion with a blood test. Before the accident that caused the concussion I never had any problems with wheat or gluten. Now I get hives and I wheeze after eating it which is indicative of a systemic response and that's why my Dr. gave me a blood test for it.

When a person has a systemic response to eating a type of food or after being exposed to a substance they are allergic to it means that toxins are being released in their brain in addition to the physical symptoms that are easily perceived. Unnecessary toxins being released in the brain can not be good for recovering from a brain injury.

If a person has Celiac Disease and they eat gluten it damages their intestines and that prevents them from being able to absorb nutrients properly. They can become malnourished and easily fatigued. And when a person is recovering from a brain injury, they need all the nutrients and energy they can get!

Some people even display systemic and anaphylactic reactions to foods but their blood tests do not show a food allergy - this is known as a "false negative". ("False positives" exist too.) But if someone has a blood test and has a bad reaction to eating food, then they would probably benefit from talking about it with their Dr. and staying away from that food.

If your son and/or his medical practitioner want to experiment with him not eating gluten for no reason then that's his prerogative. But if he has an allergy or is a Celiac, then he should definitely stay away from wheat and/or gluten. And good luck to him in trying - because it was SUPER difficult for me to remember to look for wheat as an ingredient while I was doing very poorly cognitively. And it's in practically everything! It was difficult for me to find alternatives as well. I'm doing a lot better cognitively than I was and I still have trouble with it and I was diagnosed with these food allergies almost a year ago.