Creepy guy? Boyfriend's best friend?

My boyfriend and I have been going out for over a year, and we live together, and we have a really strong relationship. The only problem, is his friends. I tried really hard to be friends with them, but they wanted nothing to do with me. They would make fun of me for being poor (they are all very high class) would just generally be rude. Of course, they never said it to my face, but they wouldn't realize I had my boyfriends phone when they would text him, and the text shows up automatically, so I saw them. So eventually I called him out on it, and he decide to distance himself from those two friends.

He has one friend that while he is jealous and mad at me for 'taking' his best friend, he has still always been rather nice, or at least not down right rude. But this friend has no sense of space, at all. While we are gone, he'll go in to our room and clean up my clothes, including my bras and underwear, or the one time he came with us to my parents house, he just walked in to their room without knocking or asking. And the thing is, he doesn't let you know when he's there. He likes to hide and listen in to conversations. Over all, it's really creepy, and you can't get away from him. He'll come over and spend two weeks there, even if you ask him to go home.

At first, this was just annoying and rude, but now I'm kind of worried. One thing that he did while he was at my house was go in to my dad's drawers and find his hunting knives. When he found them he unsheathed them and stroked the blade in a way that was really creepy. But I just ignored it, thinking he was just a city kid who had never seen a real hardcore knife before. That was before he got really creepy.

Recently, my boyfriend's sister, E, was kicked out of college on false charges. It's being dealt with and all that, but when she told him he... freaked out. He stopped texting her for awhile, which is really wierd for him. He's been in love with her for years, and is obsessed and won't stop talking to her normally. When he finally did text back, he told her "In my head I've killed your teacher three times already and each time it gets better and better." When she called him out on that, and how creepy it was, he just responded that it was how he coped. (Though he had nothing to cope with)

When she showed me the texts, I couldn't help but remember the glint in his eye when he had my dad's knives, and it freaked me out. I told her, and we were both worried, but we tried to ignore it.

About a week later, he finally convinced us to let him come over, under the condition that he left before we went to bed. Well he didn't even show up until 11 PM and when everyone tried to go to bed, he just went to another room. We even told him face to face that he needed to leave, and he responded he was. So we all went back to our rooms, and he turned off the lights and TV and it seemed like he left.

Well I woke up in the middle of the night, and in my usual bra and underwear night outfit, I wandered in to the room to find a pillow, and when I turned on the light he was there, staring at me! I was freaked out, especially since I wasn't dressed and I kind of yelled at him and asked why he was there, and wasn't he supposed to leave? He looked at me, replied yes, and stared me down until I left. I was freake dout, so I just went back in to bed, and didn't fight it, just by some off chance E allwoed him to stay.

The next morning, me and E's boyfriend are downstars talking about how this guy spent the night, and how he wasn't wanted there. We got really personal about how he was no longer welcome, and we needed to find a way to get him to leave, but it felt like someone was listening. So I got a little freaked and looked at the stairs behind us, and he was standing there, listening to us talk the whole time. Later on, I found out that my boyfriend and E's boyfriend had the same converstaion while he was supposed to be upstairs and he listened in on them too, and yet he never left.

I'm generally a big believer in following your instincts, and this kid scares me. The fact is, he knows every way in to this house, and nothing can stop him if he wants in, and even direct confrontation won't get him to leave. I've only had feeling like this before twice, and both ended up being kids who brought weapons to school to harm people.

The kicker is, I have really bad depression, that sometimes brings on signs of schizophrenia, including paranoia. Is this what I'm feeling? Am I just over reacting because of my illness, or am I having a reasonable fear of my boyfriend's best friend? What do I do? I don't want to do anything legally, I don't think I could even if I wanted to, but is there anything?