One thing I'd like to mention is that there is a difference between wheat allergy, which is a life threatening reaction to a food (such as being unable to breath/going into shock), and food intolerance/sensitivity, which in many cases is usually the gliadin protein, but there are other proteins in wheat a person can be sensitive to as well, such as gluten, which is a genetic disorder in which the body is unable to process gluten, resulting in malnutrition from lack of proper absorption.
I know, because I found out through a saliva test that I am intolerant to wheat (gliadin), soy, and dairy (casein). Like your stepson, I also went on an elimination diet. Except I had to avoid all foods that had "anything" to do with soy, wheat, or dairy. Not easy.
Then, to make matters even more harry, I had a blood test taken and discovered I am intolerant to even more foods:
SEVERE: soybean, dairy (casein), wheat (gliadin), haibut, pinto bean. MODERATE: apple, banana, beef, barley, spinach, scallop, Baker's yeast, snapper, watermelon. MILD: almond, black pepper, carrot, celery, oat, turkey, white potato, Brewer's yeast, avocado, sole. Now my eating options are even more restricted!
However, unlike a true allergy, food intolerances offer the sufferer the possibility of one day being able to reintroduce the offending food, although eating said food must be in moderation. In fact, once my system is "cleansed" of all the foods I am sensitive to, I will need to go on a four-day rotation diet. This type of diet helps ensure that you not only do not become resensitized to the foods you're currently sensitive to, but it will also try to prevent any new sensitivities from developing.
In my case, I had absolutely no idea I had any food intolerances of any kind. Never had any symptoms. The only reason food intolerance was suspected was that I suffered from chronic illnesses (high blood pressure, allergies, asthma, Seasonal Affective Disorder, GERD, sinunitis/rhinunitis (sp), atophic dermatitis/acne rosacea), and kept getting sicker and sicker. Conventional doctors couldn't find out why I kept getting sick, with a new diagnosis practically every winter, so I decided to see an alternative medicine practitioner.
Best thing I ever did. The Integration Medicine doctor I saw immediately started checking me for food allergies and intolerances. She told me that many, many people suffer needlessly from taking prescription mediciations when, in all likelihood, their medical problem is caused by food allergies/intolerances and, if they were eliminated, the person could eliminate the prescription drugs they take as well.
It's only now, after I haven't eaten soy, dairy, and wheat for a couple months (the others I just found out about right before Christmas, so the elimination diet hasn't had time to take effect yet)] that I am finally able to "tell" the symptoms if I eat something with one of the offending foods in it.
I do know people who have the wheat gluten sensitivity problem (Celiac disease), and they definitely must completely and totally stay away from anything with wheat in it, to include not sharing cooking utensils and cookware, etc. A food intolerance is not that severe or that restrictive.
Good luck to your stepson as he figures out what he has and how to cope with it, and sending strength and patience to his caregivers, as you learn how to help him.
Bless you for trying to help make this easier for him.