Well, bearing in mind the fact that your friend has every right not to talk about her problems if she doesn't want to, it also may be that she needs time to sort things in her own head before being able to talk to you. I can understand your worry about your friend. Perhaps it would help her if you wrote her a letter, telling her that you are concerned and would like to be there for her if she needs someone. Whatever you do, do not pressure your friend, or judge her / him as this is probably not what they need right now. just offer your support and friendship. That is what a good friend, who really cares, will do. I hope you get a response and keep your friendship alive.