I had a dream of a friend talking about ways she could harm herself to the point where she wouldn't survive. What does this mean? I've tried looking all over the internet but I can't find anything.

Dreams are not to be taken literal. Every single reliable source will tell you that. Dreams stem from your subconscious, what your brain is currently going through has a lot to do with your dreams. If you're going through a more stressful time, your dreams will reflect that. If you had a dream about your friend talking about self harm, you could be worried about someone or something in your life, or even have a connection to self harm. It does not directly mean that your friend wants to self harm. However; If your friend has mentioned to you before about wanting to hurt themselves or has made any indication towards that direction, there could be cause for concern.

Dreams are strange and confusing sometimes. It can means something, but it doesn't mean it always does. If it makes you worried about her, try to nicely talk with her about it. Maybe you'll find out it was just a dream or it'll be a start of making your friendship stronger :)