Doctors know mostly what they are taught in medical schools who are funded by the big drug companies and whose curriculum is set by the AMA (which operates essential as a union for doctors and mainstream medical treatments).
Keep in mind that chemo does not address the root causes of cancer, damages healthy cells as well as good ones, often damages the liver and/or heart, and does nothing to prevent cancer from returning.
The combination of oleander extract, Essiac and the Budwig flaxseed/cottage cheese (or quark) has been a very good one for many people here. A mainstream oncologist might not agree, but it should not interfere with chemo and might well enhance it if one goes that route. Whatever you do, a healthy diet and lifestyle is essential. You can find out much more about good things to do and take for cancer if you read over the older posts in this forum.
As a genuine old fart I can tell you to give your dad what information you have, and then let him make his own decisions. Having been through a few difficult diagnostic decisions myself I can tell you there is nothing worse than having friends and family, particularly my children or grand children trying to tell me what to do. I've lived through more in life than any of them, probably you too, and I'm still here.
"I'm SURE I know more than the doctor he's seeing who's the head of oncology at Univerisity Seidmans Cancer Center in Cleveland, Ohio."
With a statement like that I'll bet you think that you know more than your dad (all kids do, and they don't). And you don't know more than that doctor either.
I've had tumors in my lungs for decades, one grew a cancer and it was removed a couple of years ago and I'm none the worse for wear. Another tumor in the other lung began growing a few months ago but a recent biopsy revealed that it was neither cancer nor fungus (the only options my doctor originally thought of) and is simply an inflammation that will return to normal size in the near future.
Fear is the biggest block to healing anything (in fact fear causes disease) and when you go into fear you are not helping your dad at all. Learn that you are mortal just like your dad and everyone else on the planet and then learn that death isn't a big deal and you'll be able to handle life and family a lot better.
I'm an Essiac Tea supporter, have it, use it, and believe it's one of the best supplements out there for cancer. You may wish to also look at Pau d'arco (which I also have) and do a Curezone search for Canadian Yoda who has cured herself from stomach cancer with these two items. You can begin your search for her story here:
http://www.curezone.com/forums/fm.asp?i=336927#i