Salivation, nausea post-op

Our son had complete removal of stomach and spleen, half of esophagus two months ago and has excessive, constant salivation and severe nausea. Can't eat by mouth or accept liquid nourishment via a tube placed in intestine as bile backs up, vomits. Zofran ineffective, Compazine helps some. Does all of this pass over time and/or are there others who have experienced these symptoms post-op?