Hi Sheila,
I have to first say I'm sorry to hear of your mother's prognosis. My husband died this Thanksgiving of stage 4 tongue cancer. What advice I can offer you (and I have seen it all)is shoot for quality of life. Of course she will need those higher end pain meds to keep the pain down but seeing what I did in my husband's long 10 month battle, he would have wanted to be able to enjoy the little time he had left and he didn't.
If you did opt for any treatments maybe radiation could shrink the tumor so her pain won't be as bad but that won't offer a cure.
Some friends told me about Essiac tea which is supposed to be a natural-herb tea which builds a person's immunity and several had said on the website that they are cancer-free now from drinking it. It would be worth a shot. These kind of treatments can be costly and you do need a good three months for them to start to work so if it sounds good to you, go on-line and type in Essiac so she can get it soon. There are also other alternate meds out there (that are of course not Dr. approved) that you can find on-line or at a small health food store. We never got to try the alternative meds but what does your Mom have to lose. If anything if it boosts her immune system maybe she'll have more good days than bad.
Please know that my advice is solely just that and I don't mean to step on anyone's toes or tell you my advice is the best. It may not be but to me it would be worth a try. At your Mom's age, she doesn't need to be battered down by treatments.
God bless you and your family,
Lisa