When surgery is not an option, conservative care must be used to help bring about tendon healing without rerupture. Nonoperative care is usually by casting or splinting to immobilize the leg.
The foot is held in a position of slight plantar flexion (toes pointing down). This takes the pressure off the healing tendon. There is no risk of nerve injury as there would be with surgery. But recovery is delayed due to weakness of the injured calf muscle.
If it has been a while since the injury and there is still pain, recovery may require an extensive period of rehab. A physical therapist can help guide you and your son through this process.
Special care must be taken to protect the healing tendon from rerupture while strengthening the muscle. Most people with Down Syndrome have fairly low muscle tone, which will complicate matters. With a heart condition, if there is any loss of circulation to the feet, healing can be further delayed. The use of any brace, splint or cast will require extra skin care to prevent pressure ulcers or other skin breakdown.