He probably should be following a GERD diet. You can find a representative example at www.gicare.com. Go to the diet tab and look for a GERD diet.
Barrett's esophagus, also called intestinal metaplasia in its earliest stage, can progress to low-grade dysplasia and then to high-grade dysplasia and then to cancer.
Here is an encouraging article from the Mayo Clinic
http://www.mayoclinic.org/news2009-sct/5313.html