Child Has Indigestion, Vomitting, Bile Pigments, Difficulty Taking Food, Stools Frothy And Watery. Cure?

My 9 month baby boy suffering from indigestion at least for 7 days. Initially he was about to vomit while feeding each parts of meal. Later frequent vomiting one day,, then passing of purely undigested food (rice, sliced apple, banana, vegetables etc) sometimes with bile or without bile pigments (yellow colour). He now refuses food very frequently,, is purely on hauchpauch (rice and bean mixture) for 2 days till not getting normal stool. He passes stools once or twice with huge frothy material and strain and watery material. He is getting lethargic day by day. How can we get rid of the problem