Babies should always be fed with mothers breastmilk as its rich in building up immunity and also contains antibiotics which helps in cureing the gut health too if not able to feed then u can opt for a formula milk which z closest to mothers breast milk and that which contains prebiotics in it which will help baby with gut health and reducing stomach issues too

Babies immune system is most vulnerable till they are two years old. That's why Breastmilk is very important for babies because it has all the nutrients which are required for baby's health. Other than that try to give home cooked meals for the babies to protect them from infections

If it is for treatment then please do share your child's report here

There are important risk factors but it is is essential to know if you are looking for treatment or if you are looking for just information