Recommendations for physical therapists or fitness trainers

Any recommendations for at home physical therapists and/or fitness trainers that have experience with senior citizens? My parents (both in their early 70s) are both recovering from long term illnesses and are experiencing hypertrophy in their muscles. They were both fairly active with regular walks before they had to be bed rested for months, and my dad has lost mobility in his knees and has had a couple of falls. Now its a chicken/egg issue where they need to get back to basic movement so they can build back strength in their muscles but they can't move because everything hurts. Need someone that can guide them through regaining strength and confidence to at least go on walks again. It sucks to see them only 70 and stay bed rested and not leave the house!