Did he fall or had any type of accident? Which part of the feet is swollen? Is it around ankle or on foot?
Next Steps
To check out whether there is a fracture or not, you should first get a x-ray done and consult an Orthopaedic doctor.
Health Tips
Ask him to rest with his feet raised on 2-3 pillows. Apply ice for 15-20 mins, 3-4 times a day. Tie Crepe bandage on ankle and foot.