Advice

So a friend got the clap. She is refusing to contact all the guys she slept with about 4 or 5. She told 2 both of which came back clean. Her reasoning is that its not her problem any more. So at least 3 could have it and not even know. My question is if she doesn't tell them she has it, which means they won't know and not get tested and it causes long term damage can they sue her for not alerting them to the fact that she had it?