You don't say how old you are, so it's difficult to answer your question. Teenage boys have a weird fascination with blood and gore, so I wouldn't make too much of his postings Your brother blocked you from seeing his posts because he knew you would go to your mother. Points to you for not doing this. Even so, he has every right to block you. He just doesn't see the need for you to read what he wrote and he's right about that. Give him his space and don't let him know that you've read his posts. That will only make him more secretive and he'll block your friend. Better to give him some space and not comment on his posts. He will grow out of this phase and move on to something else. If he were in his mid 20's and had these posts, then I would be concerned. But, he's only 16. Let it go for now, but keep an eye on him. If you see his behaviour changing for the worse, his posts get more disturbing, then it would be time to talk to him and your mother. So, for now, don't say anything to anyone and wait to see how his behaviour changes or if it does. Hang in, I'm going to go out on a limb and say that this is just a teenager's fascination with gore.