I'm certainly not an expert in restoring protein digestion and which supplementary enzymes to take, but it seems to me that if your sensibilities can stand it, soup stock from slow cooking a bony joint of lamb or beef in a crock pot, seasoned with some herbs and a little sea salt, maybe with some pepper sauce like green tabasco or a pinch of curry might be quite digestible.
If the physical nature of a bony joint puts you off, is there someone else who could set it up and cook it for you, so you'd just see the warm stock, maybe with some veggies and parsley in it? A dash of lemon juice or tomato paste would be good, too. The gel from slow cooking a joint is really good for you, especially the digestive system. (Glutamine, it feeds and heals the gut.)