Disturbing writings from brother

Hi everyone. I innocently came across a notebook that has writings in it from my brother and they are very disturbing to me. Not in a harmful way, just that I know he’s silently suffering. I can’t post what concerns me because he uses Reddit as well. I don’t know how or if I should address this with him because it is very clear to me that he needs help understanding himself. He went to therapy for about a month, got put on medication and quit taking, over a year ago and has not had any help since. When I read these things it gave me an overwhelming sense of sadness and despair for him and I’m not sure what I should do.