You can definitely have gluten sensitivity causing seizures without testing positive for celiac disease. Half of those with gluten sensivity and/or celiac disease also have cow's milk sensitivity. Has he tried giving up cow's milk? Soy? msg and aspartame? These seem to be the biggest troublesome foods when it comes to seizures,although any food can do it depending upon the individual.

Also, has he tried vitamins, in particular B vitamins?

My daughter with seizures tested positive for pyroluria, a condition associated with seizures, gluten/casein sensitivity, and other symptoms. The treatment is primarily b6 and zinc, and her seizures and other symptoms improved greatly with these vitamins. This test can be self ordered...was around $60 when I ordered it years ago.
http://jccglutenfree.googlepages.com/pyroluria
http://www.nutritional-healing.com.a...ding=Pyroluria

I have known many people who have decreased or eliminated their seizures through dietary restriction and/or vitamins. The formula that works for one many be different that what works for another. Of course, not all seizures are caused by food sensitivity or nutritional deficiency, but the fact that he improved on a gluten free diet suggests it may be a factor in his. When there is food sensitivity there is often unrecognized nutritional deficiency.

Here is some info on gluten and seizures~
http://jccglutenfree.googlepages.com/seizuresepilepsy

Cara