Ron caught Harry trying to kill himself through cutting in first year after christmas. Ron stopped him, talked him out of it, stayed up with him all night, and helped him throw out his razors. After Cedric, Ron helped Harry through every nightmare. After Sirius died, Harry didn’t even have a chance to think about cutting before Ron was in the room already talking him out of it. That was why Harry never understood why Ron didn’t think of himself as a hero or even important.