Please help. Is this the right treatment for my friend?

My friend, who is 46, has just been diagnosed with BC. After 5 years of being told it was a cyst and that she was being paranoid, she finally has the diagnosis she feared. Her younger sister had BC at 36. The Dr apologised and told her that they had failed her. She has a lump of 2cm on 1 breast and 1cm on the other. She is going in for a double mastectomy next week. She has been told she will have to wait a year for reconstruction. I am concerned that, because she was in such a state of shock, and not really hearing all of what was being told to her, that this might not be the best option for her, but is, at the risk of being cynical, the best option for the Drs who may be being over cautious in light of their previous mis-diagnosis. She was told that this is the only option because she is small. Whilst she is not large by any means, she is not flat-chested. I don't want to interfere, or plant worry in her mind, so I haven't said anything to her but, if the feeling is that this might not be the best thing for her, then I will try to guide her to ask the right questions. At the moment she doesn't want to ask any questions, or look at websites etc. She is still shocked and very frightened. I am worried that she is going in for this drastic surgery too soon and/or not properly and fully informed. Please tell me what I can say or do for the best. I don't want her to find out, when it is too late, that there were other options. If, after 5yrs, the lump is still only 2cm is this not a sign that it is not particularly aggressive?