Suggest Remedy For Chronic Vomiting And 25% Brain Atrophy

My premie grandson (born 28 weeks but measuring 24 weeks, mo-di identical twin with poor placental attachment) is now 13 months old and cannot tolerate any oral feedings. After 2 months of chronic vomiting, he is being sent home on a central line with TPN. He has gut motility issues and 25% brain atrophy. Will the pseudo obstruction in and of itself be life limiting? Can it cause failure to thrive? Thanks. (He only weighs 15 pounds at 13 months).