Hello. Is the hardness due to fluid/swelling in the tissues? Is there pain in the region?
If it is fluid, and this can make tissues feel quite hard, it likely it would have increased your weight (water weighs about 2.2 pounds per liter and several liters can collect in soft tissues). Have you noticed an increase in weight since this started?
Is there weakness in the legs?
Is she diabetic?
Does she have contractures? These are tight cramps of the muscles that do not release.
Given your description, I would think she would benefit most from seeing a physical medicine and rehab doctor (also called a physiatrist). They take a more holistic approach in looking at the patient and their particular history and envirnoment. They have specialized training in both neurology and orthopedics and work with a team of therapists and community resources to get individuals the care they need.