Nothing..
If someone really is going to commit suicide (Not an act but real suicide) I'll say nothing cause nothing I or anyone say will change their mind I've been there but i survived because of my luck..That decision takes all out of you, You get to that decision when you find yourself in a place where you see no use of yourself in this world, Everything in your life feels like a failure and no one can understand you cause you cannot put your feelings in words at that point...I Have replied to tell you that this topic isn't a joke nothing anyone says can change suicidal mind...Once a person truly come to that decision in real no can change that.