Katelyn, if she is getting an abortion I don't see why she has to let anyone from school know. If I was you, I would have a talk with her. Going through an abortion can be traumatizing for some people. Try to help the best you can. If she's sure that this is the decision that she wants then all you can do is support her through it. If you would be comfortable with going along with her, I would offer to. Personally, I'm not sure if I would be comfortable with that but if I was to have an abortion (I personally wouldn't, but for the sake of "what ifs") I think I would like to have a close friend or my partner there for moral support. Does the exboyfriend know about the pregnancy?
I have several links that could be useful for you. This
link is about how to support a friend who is getting an abortion. This
link is about what to expect if you are getting an abortion. Giving your friend these resources could be useful if she decides to go through with this abortion. Here is a
link that could be useful to her if she is questioning whether or not she wants to go through with this process. This
link will tell her what to expect after she has an abortion. Finally, you might want to check out abortion laws area. This
site has teen abortion laws in the US.
I know I just threw a bunch of links at you, but I hope they are of some use. I've never had an abortion before nor have any of my friends, so I'm unable to give any practical advice based on experience. Hopefully these links will be of some use to you and your friend.