My dad was diagnosed with esophageal cancer and had the esophagus removed and the chemo and radiation and a second round of chemo because the cancer cells had spread to his lungs.  Even with the second round of chemo it didnt stop the growth on the lungs.  They are not doing any tests or anything anymore just monitoring him.  We have no idea what to expect next.  He is having trouble at night when he is sleeping with a bad cough and trouble breathing but is fine during the day.
History to hear that your father has advanced cancer. When cancer has spread to other organ like lung it is called metastatic disease. Since he has already received 2 types of chemotherapy with apparently no response his further treatment will be supportive one to palliate his symptoms. He should get medications which decrease his cough and make him comfortable. Regards