Unable to help him

My really good friend Jessie was recently dumped by his girlfriend. Now this obviously happens to all of us at one point or another, but Jessie is taking it to heart. He's hurting really bad and he won't stop talking about how sad he is. He keeps saying that he NEEDS her and that if she doesn't take him back he doesn't know what he' gonna do. She told him yesterday that she dumped him for her friends boyfriend who then dumped her. Jessie is sensitive and I'm afraid he's going to do something rash. He looks up to me a lot and says he consider me his older sister since he's only 14. I also consider him to be my younger brother. He keeps asking me for advice and I keep telling him that she's no good for him, that he deserves better and that he DOESN'T NEED her, but he just refuses to believe me. He's starting to throw depressive fits and yesterday he sprained his hand when he punched a hole in the wall. He has a history of self harm and i'm worried about him. I don't know how to help him. what can I do?

It's a really difficult situation, i was similar when my bf dumped me.
I'd say to just give him the option of talking about it whenever and try to not get frustrated if it gets a bit repeditive =P
I'd say to stay clear of saying things like "you don't need her" because he must feel as if he does but i guess try and be supportive. If he is sensitive just try and do small but nice gestures.
Sorry if this doesn't help i'm just saying the sort of things i wish that people had done for me when i went through this =P
About the self-harm thing if it is things like cutting i can message you a piece of writing that helped me to stop.
Hope this helped and good luck!

It did help. I tried it today. I told him if he ever just randomly wanted to talk or get his feelings out that I was there for him. He gave me the biggest hug ever and told me that was exactly what he was hoping someone would do for him. As for that writing I would deff appreciate you sending it to me. thanks so much for your help

It did help. I tried it today. I told him if he ever just randomly wanted to talk or get his feelings out that I was there for him. He gave me the biggest hug ever and told me that was exactly what he was hoping someone would do for him. As for that writing I would deff appreciate you sending it to me. thanks so much for your help

Aww well thats great then. I'll be able to send the writing in a few days because I have to copy it from my friend at school.