Hi Gale,
So sorry to hear about your dad's condition. Our stories are very similar..My 73 yr. old father was diagnosed with stage IV esophageal cancer 12/18/07. I live two hours from his house and I am trying to continue to be the best mother, wife, daughter, and teacher that I can be while trying to help my parents as much as possible. As hearbroken as I am (and torn between responsibilities) I count it a privilege to be able to do the few things that I have been able to do for my dad. My parents have given me a lifetime of love and support so this is the very least I can do.
I have read as much as I can possibly get my hands. The behaviors you described may be something called chemo fog or chemo head. I haven't had any personal experience with it but you may want to look it up.
I will keep you and your father in my prayers.