What kind of cancer does your friend have, did the Dr. give her 3 months with or without treatment? If I were told I had 3 months, I would do the same thing, it becomes "quality vs quantity". I have stage IV non small cell lung cancer and was diag. end of Jan. I am starting my 4th round of chemo. With treatment I might expect 12-18 months. My husband just died of cancer in Jan. of this year, so I can relate to what your friend is going through.
It is hard to know what to say to someone going through this, but try and support her whatever she decides. I would also encourage her to call in Hospice, they were wonderful when my husband was in his final stages and he was able to stay home.
Good luck to you both.