A promise to keep a secret, weighed against the need to keep someone safe, is a difficult dilemma. I'd just like to emphasize that when someone is in danger, keeping them safe comes before keeping a secret. Which matters more in the long run? But then you need to have enough information so that someone can help. Another option is to try to get your friend to tell someone in a position to help, but that isn't always easy. I hope you can find a way to get your friend connected with the help they need somehow.