I just ordered a gluten free kit to brew for a friend of mine who has celiac disease. I have a glass carboy, but another home brewer recommended I start with completely new equipment. Is that necessary? I don't mind getting hoses and things like that, but should I buy a new carboy and new bottles as well?
This page from the Celiac Disease Foundation may be helpful; scroll down to Cross Contamination. I doubt you will have any issues with metal or glass vessels or tools (especially if they are properly cleaned), but porous items may be suspect? It sounds like the note about airborne wheat flour may be the biggest issue (depending on if you are doing another brew the same day and how finely you mill your grain.) Please note that I am not a doctor, nor do I play one on TV. ;)
I think that you should ask your friend what their food preparation is like at home, or how careful they must be out in a restaurant.