Confusion

I think i'm in love with my mom's boyfriend's son.(my future step brother). I know some people think its weird but its not like we are biologically related so it doesn't bother us. I met him when i was 9 years old. That was also the first time i met his father, whom i love very much. There have always been something between me and his son. Everyone always knew it even though never said anything trough the years. About a year ago me and him actually decided to give it a shot and verbally admit that we had feelings for each other. We kept it between us though cause we weren't officially in a committed relationship. but that bliss ended soon. cause a few weeks later we had an argument(our first one).Though i see him all the time cause our parents are still together, ever since that night we haven't had a real conversation and we've both only had a "relationship" with one other person since then. No one knows about our relationship or fight except us. So when we are around each other there is tension. I was talking to his dad and his dad said that he knows that there is something going on between us. I wont tell him what happened though. Our fight we had was never sorted out or dealt with. It just happened and ended and that was it, we didn't question or try to figure it out. But i put effort into fixing things and trying to start over and at least be friends again but its like every time i try to spark up a conversation he shuts it down and puts up a wall. He doesn't even acknowledge my existence when i'm around and its heart breaking. He isn't girl crazy though. He isn't a man whore. He is respectful. but anyways a swear i think he hates me. but i cant tell what it is. His dad tells me that he was talking about taking me to prom this year. but i was like no he wasnt he hates me. he never talk to me or anything and his dad said that its because he is shy and thinks im cute and that he likes me. His dad said that he had no reason to lie to me about that. Which i dont think his dad would lie to me. His father is a good guy and he loves me lie his own daughter. but if what he said is true then why hasnt his son ever just said anything to me. I miss him so much but cant tell him cause im afraid of rejection. Should i just take a leap of faith and just tell him that i miss him or let it go?