Yes to everything Sherrie says: cakes and pies do not do well in cast iron, aluminum is better for cakes. For pies, I suppose one could bake in cast iron, but based on how my cast iron pans heat up, I think you’d actually be in danger of overbrowning the crust. The other problem is that recipes are not developed or written for cast iron, so you’d always be testing and tweaking, instead of baking perfectly the first time.
For yeasted breads, some are baked in a unglazed ceramic pot, and you might be able to adapt those recipes for cast iron, but again you’d be faced with testing and tweaking.
Just curious, what does your friend make in enameled cast iron? The only thing I’ve seen for baking that would be great is an enameled cast iron baking stone for pizza.