How do I know if a guy likes me?

I'm not sure if he likes me or not. He's my brothers friend so he spend the night at least once a week. When he does come over and we are swimming he always compliments me on my tan and then the other day her took my hand because it had all my bracelets on it and he ended up taking my hair band but he put it back on my wrist slowly and then he took my giraffe rubber band. We got out and he and my brother came in my room really late to watch tv with me and I got up walked out and came back in and he asked if I was gonna sit in his lap. I didn't know how to accept it so I declined but he still messed with my hands and the next day when my friend came over he wouldn't talk as much to me so I can't tell cause he stares at me sometimes but then when she's around he'll stare at her. So if anyone can help me please do