While she seemed to be most interested in the gluten-free beer, her comment that she could not find gluten-free food in Greece surprised me, as there are usually many gluten-free options on the usual taverna menu. The Cretan or so-called Mediterranean Diet is easy to adapt to gluten-free needs - with almost no adaptation at all other than skipping the basket of bread on the table.
It is true that gluten-free beer has yet to arrive in any quantity on the shores of Greece. Your best bet for that will be in the major cities and on the largest, most touristy islands such as Crete and Rhodes - but even then, I don't expect it to be common for the next couple of years. As an import, it is expensive for local Greek tavernas to stock - and until demand is higher, they won't give it a place on their shelves.