Jim -
You have and are most definitely in our thoughts and prayers. By now, your dad should know what he is up against. We hope it is not as bad as it sounds.
Please tell him to NEVER GIVE UP!
7 years ago, my mother was diagnosed with a golf ball sized tumor in her L lung...inoperable! With aggressive chemo and x-ray, they were able to kill that SOB and today, she has been Cancer Free for almost 5 years.
ATTITUDE and FAITH are key imho.
The Angel that sits on his shoulder will watch over your father.