I am almost 3 months post-treatment and have stomach issues as well (that no one can figure out). I even posted about this before. Its gotten better to some degree but still going on. A few things to consider: constipation, acid reflux, Cdiff (infection) and ?tube feeds/food sensitivity. I did not have a PEG but drank only Boost VHC for almost 3 months and I think some of my issues were due to the soy or dairy protein in it. I got some relief just from eliminating the Boost. And agree with everyone else here; all sxs at this point should be considered cancer or treatment related, and should be dealt with by the oncologist. Good luck; I hope he feels better soon.