What do u do if a guy like you but you don’t ....

So I have been friends with this guy since I was 7 years old (I’m 16 now) and I really good friends with him we are like mates. No joke when people come up to me and ask why we are always talking I say we are cousin no joke I say we are cousin because 1. We look alike 2. He like a cousin to me 3. That’s how I see him you know as a friend and some people believe we are and yeah he like a cousin..... BUTT. He being more how do I say it REALLY CLOSE LIKE I HAVE A PERSONAL BUBBLE (like annoying and more talky) and everyone saying he has feelings and shit and the other day I was at the beach with my friend and he was there as well and like this is the first time we have like hang out (because we only talk at school tbh) . And I was in a bikini and he was just looking at me the whole time ( like looking at my boobs and shit and idk it was weird and dude I was like fully covered and shit like I don’t wear ckeecky bottoms like no I’m very covered) and well it was werid u know and now all he does he text me saying wyd and shit like no ew your a brother to me dude but idk I have been avoiding him and he’ll just walk up to me and shit and get the same bus as me and sit near me and valentine is coming up and he always asking who my crush is and shit. Look I know that story made no sense but I’m worry he going to do something for valentine and I just don’t like him in that way even imaging it make me sick like it’s dating your brother LIKE HELL NO 🤢even worst I don’t wanna lose our friendship like he ask me out I would tell him to like stop joking like I don’t wanna do that 😔