My Mom has Celiac and my sister and I have type I. Very close relationship and quite often people do have both. The problem with the biopsy is it can be scattered damage wise and I believe they can miss the damage. Usually though, they consider it the best way to tell.
Howevever, blood test wise, if his ttg is positive that is pretty much a sure fire thing.
If the gliadin tests are positive, it isnt such a done deal.
Quite often people who already feel bad, will just go gluten free and forget about it, without even having a biopsy. But at a young age, you probably wouldnt want to put a child through a life of being gluten free if they didnt have to.
I would say, go to Celiac.com and look up ROCK-Raising our Celiac Kids, and Danna Korn.
She has a wonderful book out for Celiacs, mainly making it fun for the kids to be on a gluten free diet.
She answers her Emails, and has written me back every time I write her.
Her book is Wheat Free Worry Free, and you can find her at that web site I mentioned (as well as much other info.)
The good thing if you do have Celiac, the damage heals as soon as you end up on the diet (which is pretty complex). The hard thing is not being able to eat what other people eat, and having to be very very careful in restaurants and even hospitals....because people dont get it! One speck or crumb can make you sick.
I hope you dont have to deal with it, but it is a good time to be living with the condition because more and more restaurants and stores are carrying gluten free foods and people who dont have to go gluten free sometimes still choose to do it because of health reasons.
But do look for that ttg test, because I'm pretty sure that is the one they say means that a positive result is 100 percent positive for celiac. It means the intestinal damage is already there.