Hello dear,
The symptoms as mentioned in your post can be attributed to musculo-skeletal injury.
The swelling is caused due to accumulation of fluid and blood (haematoma) following the impact.
Symptomatic relief can be obtained by application of ice,
analgesic &
muscle relaxant gel, intake of analgesics like
Diclofenac +
Serratiopeptidase (to be taken after food) and
Pantoprazole (to be taken 30 minutes before meals).
Supplements of Calcium & Vitamin D can be included in his diet which will help in strengthening of bones.
If symptoms still persist, it will be better to consult his Doctor/ Orthopaedician for a proper clinical evaluation.
X ray of the leg and ankle joint can be done to rule out any pathological cause for the symptoms.
Till then, he should maintain adequate hydration & nutrition status, take proper rest and avoid stress.
Wishing him a Good Health.
Take care.