cancer for three

Hi, my 93 yr old grandmother was diagnosed with stage 3 invasive ductal breast cancer about a month ago; just to be sure, the doctor did an aspiration biopsy and a pet/ct scan; the biopsy confirmed the stage 3 cancer; the pet/ct scan showed that she had another tumor in the bones, it is caused by the breast cancer, but it's a separate issue; it also spread to the scrotum and vertebrae and some other places I can't remember; right now she is taking arimidex to hopefully help shrink the tumor which the doctor said could take up to 2 months; after that, she will need to go through surgery (mastectomy) followed by radiation; she is able to make decisions on her own, which we are making her do, but it takes several times to tell what really could go on because she has short term memory loss; this will only happen if she agrees to it and really understands what is going on;  if you looked at her, you wouldn't even know that she has cancer, she's in good spirits and her favorite lines are "it is what it is" and "whatever will be, will be" as the doctor would tell what to expect from this, as well as the family.  She is also seen by a home health aide/nurse to take care of a wound thing caused by the breast cancer (the cancer broke through the skin which is how we knew something was up in the first place); my dad and I are the primary caregivers for her (I'm 21) and have been there for everything and will continue to do that as well; the only really frustrating part is that her other children live in other states, including one who lives out west, and everyone seems to have their opinion about this and my dad and i don't think/believe they believe what we tell them about my grandmom/their mom and one even acts like we don't do anything at all; also frustrating is that she has never been sick her whole life besides getting two knee replacements but that's not being sick; she's been very independent her whole life, and it's a little hard for her to accept that she needs help to do everyday things and can't stand the attention at all; i do have several questions, what can we expect out of this regarding her age and she has severe knee pain (it started around the time of the diagnosis, so we didn't think much of it, but is it possible that the cancer spread to her knee (i believe it spread to the thigh), but the arimidex can cause joint pain/stiffness as well

her cancer diagnosis comes off the heels of two other family members who have it too; her oldest daughter (about 64/65) got breast cancer 7 yrs ago, opted against treatment then, but has since gotten treatment and is on the road to recovery; her youngest sister (83) got diagnosed with early stage breast cancer last year and underwent 33 radiation treatments; however after having a recent mammogram done, they found something and she went for a biopsy, where they discovered a tumor; she meets with the doctor tomorrow to get the treatment plan, which was surgery on the phone when he called to tell her the results and she'll have to stay in the hospital for a couple of days

 it has not been too easy to deal with everyone having it, or just knowing the my grandma has it, but some family members are trying to stay positive; her two doctors are optimistic that she'll be okay, so i figure I might as well be optimistic as well

Megan