I suggest that she shud just breastfeed as it helps with all problems. With regards to this ask her to give ors solution as well as add prebiotics in her diet to help her get immunity.

Hey Vandita, Do ask your sister to continue breastfeeding. she can try this position http://app.babychakra.com/feedpost/179803?ref=SEEM26882& to promote feeding. Additionally ask your sister to follow the doctor's recommended treatment too.

Hey Vandita. Breastfeeding does help to a child lot better. It usually works in a manner where hydration from the mother will work more effectively in the first 6 months. We cant keep the child dehydrated, please ask her to follow the doctors instructions . it will give the child some relief