I am still working on my own treatment plan. We have had a series of tests (biopsies, PET scans, and CT scans) over the past four months. During this time, I began (and completed) my first part of treatment. In my case (T2N1M0) adenacarcinoma of the esophagus/barrett's, that consisted of six weeks of chemo and radiation therapy.
However, your dad's plan may be different depending upon the staging of his cancer, his own health condition, and his personal preferences.
I found it useful to rely on GOOD reliable resources on the web (Mayo Clnic, Sloan Kettering, MD Anderson, American Cancer Society, etc.) to better educate myself and my family on this horrible disease.
I hope that you will find resources that will assist you and you will take from those the questions you and your dad may want to ask of the doctors handling his treatment plan.
Good luck to you!