My friend bought me a forget-me-not necklace, there are lots of sites for baby loss, where you can buy some lovely necklaces or bracelets etc....they last forever too. You are right about the flowers, i was sent loads after my first miscarriage, and was so sad when they died. I lost my 2nd baby at 19 weeks and delivered him in hospital on the 20th January 2011. You are a very good friend for looking for advice on how to deal with her loss.
From my perspective it is important to acknowledge her baby as a baby, does she have a name yet? Always refer to her baby as she does, whether this is "baby" or "baby's name". Never tell her she is lucky to already have children, or depending on her circumstances lucky for anything (she will be feeling very, very unlucky right now). Tell her she needs to grieve and perhaps help her to make the decisions that will be very hard for her to make....post mortem, does she want a service etc etc...I made many mistakes in my decision making, because I was so numb more than anything. She will regret not making the right decisions, so she must consider them carefully. Tell her it's ok to laugh sometimes in the months to come, it doesn't mean she loves the baby any less. When she's feeling really down, music can often help, whether sad to make her cry, or happy to lift her spirits. There is so much more, but all I can say is, I have not gotten over the loss of our little boy at the end of January, and I probably never will, and although I can function as a human being again..inside I am so, so sad. Just keep being there for her, and don't avoid talking about the baby and her loss, even months afterwards.
You are a good friend, good luck.