So sorry to haer of your Dad mine had EC and my husband also, so I know what you are going thru.
The good news here is that it has not spread even though you say it has not shrunk either my husband was on taxotere and I yhink cistoplan ? but is your Dad not having radiation? That is what got rid of my husbands tumor stage 4 and 4cm, we got asecond opinion and went to M.D.Anderson we had the chemo and radiation done at a hsopital here but they gave them the presciption for it.
My husband was on a feeding tube as the radiationis tuff on the esophagus but it was worth it in the end as he was cancer free for 1 year.it sounds to me like you need a different chem and if pssible radiation, try to seek a second opinion M.D are really good and worth the effort.
my prayers andd healing hugs are with you all. keep me posted, good luck.