You are not here to fix anybody. You cannot, and trying is the fastest way to do harm. What you are here to do is much smaller and much rarer: be one person who listens to somebody without flinching, without advising, and without making them feel like a problem to be solved. Most people who write to us have never had that once in their life. That is the whole job, and it is enough.
A volunteer is not a therapist, not a doctor, and not a counsellor, even if you are qualified as one somewhere else. In this role you do not diagnose, you do not treat, you do not prescribe, and you do not run therapy. You listen, you respond like a human being, and when something is beyond you, you hand it to somebody whose job it is. Knowing that line, and holding it, is what makes you safe to talk to.