Why does my ex do this, best answer 10 points?

He comes to me whenever he needs comfort, like when there's bad stuff going on in his life. He im'ed me on facebook last night saying call me please i'm going to kill myself please call me. So i told him to call me and he did and he was just crying about how much trouble he's going to be in because of something dumb he did and i talked to him for an hour or two. Then today i texted him asking how everything was and he ignored me. I went on facebook and saw he was online but as soon as i came on he went off. Why why why does he do this? It makes no sense.