reflux disease generally reduces in severity by 5/6 months...severe reflux needs to be treated. if vomiting continues beyond initial months, other causes have to be evaluate other causes

Gastro esophageal reflux disease usually settles by 6-8 months. At 9-11 months if there's repeated vomiting , it needs to be investigated. Also weight gain appears to be slow. Needs evaluation by Pediatric Gastroenterologist to rule out causes like Coeliac Disease. I recommend basic tests like CBC, Blood film, RFT, LFT, Immunoglobulins & Stool / Urine Routine along with TTG for Coeliac Disease to evaluate the causes. Earlier the causes are investigated, the better.