I'd say "newly decided" rather than "newly diagnosed," given her history but it's good to know that about gluten hiding in otherwise-safe-looking dishes. ((snip))
Oh boy, does it ever! Sausages, meat patties, processed deli foods, a LOT of frozen foods including chips (fries to those from the U.S.A., I gather) - they tend to get wheat added as an anti-caking agent, which is one reason why gluten-free frozen foods are usually stuck together in one solid lump in the bag - and a surprising number of canned foods and sauces that you wouldn't expect to have wheat anywhere near them.
I'm not gluten-intolerant, but I do have to keep wheat out of my diet at the moment, along with a whole shopping list worth of other items. You would not believe
the number of things that have wheat in them (and the ones that don't have wheat usually have soy, and the ones that don't have wheat OR soy have corn, and the ones that don't have wheat OR soy OR corn have onion, and and and...).
I'm so, so glad that the latest results from my elimination diet and testing indicate that wheat and soy aren't among the things I'm going to have to avoid permanently, because of the insane number of things they're in.