What can you do for your friend that just went through a really bad breakup with her boyfriend for over 2 years?

Whenever a friend is going through something hard, there really isn't much you can do. All you can do is let your friend know that they can talk to you if they need it. If your friend decides to talk to you, you don't have to offer advice or anything you just need to be willing to listen to them. I know its tough and you might want to do more, but that is really all you can do.