Sarah - Welcome to the forum. It is good that you are beginning to question the "there isn't time.." comment. Some cancers are very aggressive, but that should not preclude getting an informed opinion about what to do. Head and neck cancers are a bit different than many other types. For this reason, it is VERY wise to consult with the cancer care centers that have dealt with this condition frequently.
There are many things to think about: Surgery or not; radiation - how much, what type, etc.; types and timing of chemo; dental concerns with the radiation; etc. Most new patients are so overwhelmed with the speed of events that they fail to ask good questions, or fail to be appropriately skeptical of suggested treatments.
There is more than one way to treat cancer. Some advocate surgery, some do not. Some use lots of radiation, some less. Some use these drugs for chemo, some use those drugs. You don't need to know which ones are right for her - only that whatever decisions are made should be questioned. Why these drugs? What other treatment is possible - so why this one? Getting the docs to defend their decisions helps you understand more about what is going on, and reassures you that they didn't pull a treatment plan out of a hat.
Get the insurance people tuned up and running so there are no surprises later. Get serious about nutrition and hydration NOW. Don't panic. A cancer diagnosis does NOT mean "the end". There are MANY, many people who win this battle - more every day.
Sooner or later they will 'stage' her cancer. That is important info, but not critical. My cancer was VERY advanced, and I'm still doing fine three years later. Staging will help the docs make recommendations (not decisions) about what treatments should be completed. Get people involved in the decision making. Passive patients don't do very well. Active, participating, question-asking, patients do much better.
Don't worry about not knowing all the technical stuff. Ask questions anyway. There are no stupid questions about cancer. Make them tell you what they recommend, what they are doing, why, what is the up side of this action - what is the down side? Ask questions. Take a tape recorder to the Dr appointments. Take two people to listen and ask. Write things down - questions and answers. Make the docs repeat the answers until you get it - for me that was often 3 or 4 times. Docs that don't listen, or won't patiently answer questions.... are the WRONG docs. Get a different team.
More than ONE doc is needed for this. ENT, chemical oncologist, radiation oncologist, oral surgeon, dentist, physical therapist, etc. It takes a TEAM to do this well and properly.
Read this site. The home page will lead you to hundreds of pages of high-quality info about our cancer. Get informed. Do it quickly. Remember that your sister is the CUSTOMER and the docs are the SELLER. Be hard to please. Be a fussy shopper. Demand their best service. Take nothing for granted. Get second and third opinions. It can be done quickly and NEEDS to be done. Come back here often. Get you sister on here. Get her daughter on here. We can help. Really. Be strong, Tom