Well that has to be very frustrating for your family.
I know I've also seen stuff about people getting better within a couple of weeks... but from what I've seen on celiac boards, people responding to a gluten free diet often take months to see actual improvement, and age doesn't seem to be so much a factor. Sometimes children improve faster, but I've seen on celiac boards where children can often be slower than adults to respond to the gf diet.
I know in myself, with my problems, improvement was very slow and gradual, so much that I finally resorted to a chart to track symptoms by months... I saw improvement about every three months for 2 years. By then, things leveled off quite a bit. I'd tried going gluten free once before and thought I didn't see improvement at all, and then gave up... but on hindsight, I didn't actually ever stay gluten free long enough to notice the very gradual, stepwise improvements. Thanks to reading message boards and other celiacs' experiences, I got the idea to try again, and will alway be gald I did.
I don't know as much about RA as I do celiac disease... but I would wonder if improvement might also take some time...
This study of vegan plus gluten free for RA seems to indicate they allowed a full year for improvement in various RA scores:
http://rheumatology.oxfordjournals.org/ ... 40/10/1175
Hang in there! You're searching for answers... and one of these days I hope you'll find them!