Gastric n intestine ulcer. 5 years long?

My friend suffering from gerd which found in endoscopy n small multiple ulcers in large intestine in colonoscopy n his symptoms leads to feeling heaviness most of time in side n back of stomach taking vit d3 60000 iu n b12 injection ones a week since 6 week. Bt still have feeling heaviness and gastric n burped problems. My question 1 heaviness is due to gas or due to multiple ulcer in large intestine?? 2 not clear toilet always like semi solid or liquid motion n passing lots of gas is due to gastric?? 3 ulcerative colitis n ulcer are same thing ?? 4 he dont have any bed habits like smoking n drinking at all. So why problems is continued since 1.5 years long?? He not feel any kind of bloating or acidity issue not related problems associated wid appetite he is only feel heaviness in right lower side abdomen n gas is traveling inside the stomach wid sound no pain at all never feel all usg abdomen n blood test normal exp vit d3 40