((HUGS)) Mattieu!!!
I don't think we ever get over the pain of losing someone we love, especially a sibling. My mum lost her sister at the same ages that you and your brother were and to this day she still talks about her and misses her. She wonders what she would've grown up to look like and all the things she would've grown up to do as an adult. She remembers her sweet nature, how quiet and loving she was and I know it pains her greatly that she never got to grow up with her.
Whatever the future holds, treasure the memories of your little brother. There isn't a person out there who can tell us what happens after death, we have to experience it to know it. So who knows, you may indeed get to meet him again, in another time, another place . Thinking of you on his birthday x