Helping someone who helps people

I wasn't sure which category to put this under, since it's a bit removed. I've put it here, since it's similar to trying to help someone who is dealing with someone else committing suicide - but instead, dealing with people who are *likely* to commit suicide. I am a freshman college student. There is a friend of mine who, in highschool, was the rock of support for at least three different people who had tried to commit suicide. One of them considers her the only reason to live; she's directly saved another's life. Understandably, having to deal with this kind of pressure has left her slightly traumatized, and additionally now that she is no longer in direct contact with these people she's extremely worried about them, and doesn't actually have much reason to think there's anyone else out there caring for them. My question is, how do you help someone like this? Basically, to help someone as they come to terms with the fact that there are limits to how much they can help others?

You have to let her know that she did the best she could when she had the chance, she didn't turn her back and you're sure they are doing great because she's the one that helped them, & now she needs to worry about her life