What's the matter with my brother?

I'm a guy and I'm 16 years old. My parents are dead so I'm living together with my older brother who is 30 years old. He's really nice and he really cares about me but something strange is happening in the last weeks. It all started with a questions about have I had , have I already kissed, have I had a girlfriend. I denied it all because I'm shy and I haven't tried anything yet. After that he has started to touch me, caress me. It is all very confusing to me because I'm not gay. My brother is not married and I don't know does he have a girlfriend. Yesterday we were both watching TV together and suddenly he hugged me so tightly that I couldn't move at all. When I asked "why" he just said "you're cute, that's all" I'm no match for him. I'm afraid. He's my brother and I love him, but why is he acting like this?