12yo and supination

My 12yo son was born with a bilateral clubfoot and was treated with the Ponseti Method. We have noticed lately that he tends to walk on the outside of his affected foot. I took him to a physical therapist who told me that he has calf tightness/weakness and a lack of range of motion. He suggested that I see a doctor first before trying physical therapy as they may recommend surgery first. We live in Alabama but are willing to travel to whomever you guys suggest to be the best to see in this case. Since he is post-Ponseti and almost a teenager, I would like to see someone who has more experience with that area.