Endoscopy findings - lax ge junction, gastroperesis, scalloping of duodenal folds

I am presenting a male patient of  45 years old with c/o Pain Abdomen, fullness of abdomen, flatulence and indigestion on-and-off-Diaorrhea. No weight loss, no nausea/vomiting, normal appetite. Significant past history of continuos in take of Pantoprazole 40mg (PPIs) for more than 05 years with alternate day in take of alcohol. On investigation Vitamin B12 much lower than the normal range, Endoscopy findings Lax GE Junction, Gastroperesis and Scalloping of Duodenal Folds.

Biopsy was taken from D2, Histopathological report suggesting increased intraepithelial Lymphocytes (35-40/100 cells) on D2 biopsy fragments.Normal villous architecture and no neoplasia, no parasites identified. Presently on treatment of Tab CINITOPRO bd for a month and SOS Antacids. Please suggest the diagnosis or DD with correct  mode of treatment and do the needful.