What should I do?

Hey people,

This will be longer:

My younger brother (12) and I (16) share a room because we're currently building a house. And when my mom is at work in the evenings, he likes to be on his phone, gaming, and watching TikTok late into the night. And there's nothing I can do about it. When we argue, he sometimes hits me a little. And when I hold his arms, or legs, etc., he starts to "cry," but there are no tears; he's just acting. He's very good at tricking and does everything to his advantage. Whenever you want something from him, the question always comes up: And what do I get out of it? I never know if he's just pretending or if something's really wrong. I always try to protect him from the mistakes I've made, so he doesn't have to endure what I've endured. But he doesn't let anyone take anything from him, and when I want something, he doesn't care; the main thing is that he has peace and quiet and can play games and watch Netflix, etc. I don't know how to handle this. I just want to help him and prevent him from making the same mistakes, but I think he's just using me. He comes when he needs something, but when I need something, he's too lazy and doesn't do anything. He also likes to play games with me. How should I behave? What should I do if he's on his phone in the evening and no one else is there but me?

Best regards

Tim