Your friend must be completely horrified and I would be too. The thing is if you really get through to her and getting her to keeping the baby alive, you might want to persuade her to having an open adoption so that she doesn't have to support the baby, but she can still see it. This would probably be the best idea for a 15 year old girl. If you watch the Secret Life then take some of the advice they give on that show. It may really give you some ideas of how to help out your friend in her time of need. I hope this helped
Keep us posted on what you decide to do!