My little brother thinks he can read my mind?

He is a little turd at this. When something happens to me, caused by him, he denies it. He says he knows me(even though we are related, I hate to be myself around him. You'll see why) and that he knows what I'm thinking. I got him in the ****ing head by a bb shot by him, he said I was lying, he knows what I'm thinking. He thinks he is the best shot, thinking that the barrel was facing the opposite way, when in fact was more my way. I think they think that I do this for attention, but they can't take the hint when I lock myself in my room to get away from them. When Wyatt said he wanted to cut my throat because "I think I'm badass." or having an angry tone. That ***** is psycho, I have acted how I usually do, informative and emotionally dead. The bastard thinks that history is pointless and he is 14, he needs entertainment other than guns, knives, cartoons, and rated M games. He has the crap up to his head, he believes his own lies most the time(I say that because even after we show evidence, he still sticks to the lie). He had a knive at my neck(sharpened knife) several times already and would have cut my throat if I didn't tell the reality of cleaning the mess to him. After that, he said he was just holding me off or trying to scare me off. But I know better, how could you send someone off if you had a grip on him and a blade at his throat(scratching the skin)? You can't, unless if you risk dying. Why does he believe in his lies? Why does he threaten to stab even dad? Why does he believe he knows me when he has never taken time off the video-games? I want him sent to an asylum to get him fixed and with minimal chances of harming someone(especially the therapist). Please help me?