First try to hydrate your child with fluids like buttermilk, ors etc so that he passes urine adequately
Then instead of nutrolin b give econorm or enterogerminia twice a day
Then also give Z&D drops 1 ml once daily for 14 days
Restrict milk intake during the duration of diarrhoea
Antibiotics not necessary
Next Steps
if not voiding urine or very tired with sunken eyes he may need IV fluids