Hi RedRiding... welcome to the club!
it does sound likely that's what your DS has got. we opted not to have the biopsy, as we felt it was too invasive for little DD and also we got her on the GF as soon as we got the blood results back and didn't want to effectively keep her poorly for another 6-8 weeks whilst we waited for an appointment. But her antibody blood test results were 200 (anything over 10 is positive diagnosis), so it wasn't really a grey area!
we haven't gone completely GF as a household, but one thing i have found is that, as she's got better and better, she has become more sensitive to tiny trace amounts of gluten, so we now have separate toaster/butter etc and she can't have chips in a restaurant if they fry them in the same oil as the fish goujons.
there's also trace amounts of wheat in really uneccessary things... like normal brand cornflakes & rice crispies/ stock cubes/ cloudy fruit juices(!) etc, so you have to buy special versions. we've had great success with the GF ranges at Sainsburys and Asda, as well as home-made chicken nuggets/ fish fingers using crushed GF cornflakes instead of breadcrumbs.
my DD is still young (2.5) but i'm amazed at what a great understanding she has of what she can and can't eat and she never kicks up a fuss when i say she can't have the croissant/cake/sausage/biscuit that she wants. she must really remember how crap she used to feel all the time...
that said, i'm not looking forward to the kids party phase, especially when she gets to an age where she doesn't want to be different from her friends :(