next step for mom?

Hi all. I'm not sure if you can help me, but I posted here once before and was overwhelmed with the great words/assistance.
My mother is Her2 positive and was diagnosed with BC mets to the liver in August. She was on a combo of taxotere/carboplatin and herceptin until recently... her MUGA showed her heart wasn't taking it well.
Her last Pet Scan showed the cancer had stabilized or shrunk, so her doc took her off the chemo and herceptin and just started her on femara.
I guess what I'm wondering is if any mets women out there are/were on femara, how well or poorly it worked for you and if you have a feeling whether this is a good idea to go on next.
When I went with my mom to her 2nd opinion early on, that doc suggested the second step be the tykerb/xeloda combo. Wondering why they're doing Femara instead...

Thank you all.
-Amy