Hi, Welcome to Health care magic forum.
It appears that he has an abscess
, with the pus spreading to the ankle and foot. The other possibility is the filarial infection.
I advise you to consult a surgeon for diagnosis and treatment. You may need to have the incision and drainage
of the swelling, and use medicines, for healing.
Take more of green leafy vegetables, pulses, sprouts,and
protein rich foods to hasten the recovery.
Wishing for a quick and complete recovery. Thank you.