I never actually went through any of this with my older brother. I have, however, had to deal with friends' little brothers, and the only thing you can do is make friends with them. Force, having witnessed the effects myself, makes everything worse. Find something in common. I assume you both play Blockland, so have fun making a build together or something. It's not tough.
Also why are you so possessive about the XBox? I'm never mad when my siblings use my consoles.