good advice from everyone here so far. i would also like to mention that most pain meds can constipate, so you might consider getting her something to alleviate that just in case.
i had implants a year ago, under the muscle, and i must say, i didn't have much pain past the 2nd or 3rd day. it all depends on how big you go, and also how the surgery is done. my surgeon cauterized after cutting the muscle and supposedly that speeds up recovery and makes it hurt less. i was back at work after a couple of days.
no lifting, so make sure she has the laundry done, plenty of button up shirts pull on pants. wash and dry her hair for her so she doesn't feel ugly.
she may want to sleep in a recliner or with some sort of support where she isn't laying flat. this makes the swelling increase, and was when i had the most discomfort.
also, the first night, make sure she takes her pain pills BEFORE she starts to hurt so she wont have to suffer until they start to work. at night, wake her up to take the next dose about 30 minutes before. if you don't, by the time she wakes up and needs it, she will be hurting.