This is such a tough one . First, if you take the 'food issues' out of the equation, would you want to spend Thanksgiving there? If yes, then I'd lean toward saying 'go for it'. How many people is he inviting? Could you have them at your house?

If he is saying~ "I am researching gluten sensitivity since i cook for a number of people who are afflicted", it shows he really wants to make the effort to include you.

If you decide to risk it.... I would definitely plan on offering to take a few dishes along. Let him know how much you appreciate his willingness to accomodate you, and let him know you'd like to be part of the menu planning, double check ingredients, etc. You might suggest some low risk items, like steamed brocolli. Once you find out what is on the menu, you can offer to bring along the things you'd worry about most.... say a green bean casserole dish~ or dessert~ or gluten free dinner rolls.

I'm just happy to be having our annual Turkey fry here, again, so I don't have to worry about it. Looks like we will spend all day frying Turkeys, as both my daughter and son want to do an 'extra' one to take back home.

Cara