My daughter has Aspergers and we went gluten free almost 6 years ago. When she was first diagnosed, the doctor wanted to medicate. I took some time and did some research and found a link between Gluten/caesin and aspergers/add/adhd. So I gave it a shot. You may want to check on removing caesin as well (dairy).
It can take up to 3 months to notice a difference - so please be prepared for that. Almost immediately, her daily headaches and stomachaches were gone. Within in 3 weeks my daughter said she felt "happy" for no reason - something we hadn't experienced before. And here we are almost 6 years later. She's 110% better - it's really amazing. If she happens to get some gluten, she will have a "meltdown".
We eat very natually. Meat (unprocessed), veggies, eggs, fruits, potatoes, rice - do not contain gluten. If you buy processed foods, like hash browns or tator tots - you have to read the label as it sometimes contains gluten. Stick to name brands.
Bread - I make in bread machine or I buy UDI's (tastes most like real). I do not make from scratch as it's ridiculous!! I buy a box for the bread machine. We use little bread it's expensive and doesn't go far. My daughter is almost 16 and eats a lot of salads for lunch vs sandwiches. But when she was younger it was a lot of peanut butter and jelly - she preferred over meat.
I shop at Walmart and then go to a grocery store for what I can't get (Udi's bread, for example). But like I said, I don't buy a lot of processed foods (gluten free or otherwise). Cereal, we stick to Chex vs other gluten free ones (cheaper).
I found a website that listed all the ingredients that are "gluten". I laminated it and brought it with me to the grocery stores. But I will say it's much easier now than it was when I started.
Gluten is in everything - soaps, shampoo, conditioner, deodorant, laundry detergent, chap stick, make up, stickers, play dough, stamps, etc. I don't know how old your son is and how much product he uses. But I just called the companies of everything she used to find out.
If you want more information - please PM me . . . I could go on for days!!