I personally think and feel that you can forgive someone else regardless of if they've acknowledged what they did to hurt you. If you wait for that to happen, you might never EVER be free of anger and resentment towards someone.
You can't stop them from self destructing, but you can be their friend. You can pray for them, and ask God for his help in talking to them. One of my friends taught high school last year and his heart just broke for his students. So much pain, anger, confusion...that is just sad. :(

*huggles*