Last time I was there, I'd say "decent". They can make some of the sundaes gluten free. They'd probably clean a milkshake machine so you could have a gluten free malt. I think they offered us bunless burgers and baked fries. They at least occasionally have gluten free buns. It took a long time to get a chef, I think he came from another restaurant, and I know our food was cooked in another kitchen and brought over.
There's no such thing as a gluten free malt. Malt by definition is barley based which means gluten. You can get gluten free milkshakes but not malts. If a restaurant is telling you that they're giving you a gluten free malt then run, do not walk, to the exit.
I already answered on the disabilities board with some details about B&C.