How Can Abdominal Pain On The Right Side Be Treated?

my husband is 67 past 2 years he s only able to eat less than 500 cal daily ; systems are stomach pain on the right side , nausea and vomiting and a lot of gagging changing bm daily: his test cleared are: blood work - stool test - chest xray - hida scan - 3 different ct scans - endoscopy found small shallow ulcers in the antrum no bleeding mild esophagitis esophagus normal - small Hiatal hernia husband is a retired Vietnam vet has congestive heart failure - high blood pressure - high cholesterol - copd - PTSD is on oxygen and his cpap nightly and oxygen during the day as needed Dr from Portland Va has taken him off three of his meds for two weeks to see if theirs any change with systems (that he s been on for years) that cause nausea and diarrhea : husband hasn t been gagging stool is different all the time, hasn t had stomach pain as often, eating or the lack their of hasn t changed please help and suggestion would be welcome primary Dr is at a loss