vomiting post op

A friend had an esophagectomy over 5 weeks ago.  She continues to vomit several times a day and is unable to tolerate clear liquids--even water let alone the 6-8 small meals continually suggested.  Reglan and promethazine have not helped.  She is not nauseous and not in pain but the vomiting continues.  What can be done to help with the vomiting or get it stopped? Her vomitus is foamy and phlegmy.