A good chunk of their menu (sandwiches, burgers, pizza, pasta) is available gluten free. The fries are gluten free by default. The owner apparently has celiac disease - they know the procedures to take, are extremely careful with cross contamination, etc.
I had a burger and fries, it wasn't the greatest meal of my life but it was OK and I felt fine afterwards.
— Very
— Gluten-free items are marked on the main menu
— Some
— Average