we should diffrentiate different diseases and exclude kidney diseases-glomerulonephritis, immune diseases-rheumatoid arthritis, reactive arthritis and other. At the first do routine analises -blood and urine tests, then renal function test and rheumatoid tests,common protein, antistreptococcal antybodies, antibodies to Chl.and Myc.trachomatis. For relief of his pain he should stay warm in the bed, do bandage of feet, apply nonsteroid ointment - diclofenac or voltaren gel. You can give him pain killers in form of nonsteroid antiinflammated medicines- paracetamol and other. He should not jump or run, because swelling will increase. You should start to give him antibiotic-ofloxacin. Best regards Dr.Svetlana