Diabetic. Swelling, Soreness In Foot. MRI Shows Round Area At The Ankle Bone. What Could It Be?

My husband is experiencing swelling and soreness in his right foot area......then all of a sudden it is so painful that he cannot even walk on it. An MRI shows a round area at his ankle bone but we don't yet know what that might be and are waiting for an appointment with a orthopedic doctor. I have been reading about Charcot's foot and it seems so scary and so painful. He is now able to walk in it after 3 weeks but it still swells and is so painful. He is a Type II Diabetic and his blood sugars are hard to control. What do you think might be happening. One person told us it was like his instep collapsed and he needs new insteps and new shoes. But they don't seem to help in fact they seem to irritate it more. Any suggestions???