Can anything be done?

A friend of mine recently broke up with his girlfriend and she has been posting things on her tumblr accounts full of false claims that he is threatening her and her friends (he cut off all contact with her) and accusing him of rape. She has also threatened to send people after him to beat him up/kill him if he shows up at any events that she or her friends go to and is saying he is going to one when he is avoiding it BECAUSE of her threats against him. She even began naming me and a few other people and claiming that we “let” her be abused and did nothing about it. Is there anything we can do? I know there are legal rights, but the fact that its online and free speech and all that kind of protects her from being stopped.