My best friend and I are in love but haven't admitted it

I'm a 21 year old girl, I met a guy 2 years ago in college who was grieving the loss of his only sister. He was very closed off and quiet but I've always felt something different about him. By coincidence, I did something that reminded him of her; his sister and I guess that was the reason why our friendship first started. He thought he saw something beautiful in me, something that resembles his sister very much. He started talking more to me, telling me all about himself, asking me about myself. By time, we began to have a very deep connection with one another and he was astonished by how frequent he finds himself talking and spending time with me. He was very sweet, caring and protective of me, among all the girls he knows, I'm the one he treats differently. He had a habit of getting too close with me, then backing off. I started developing feelings for him the more I knew him and I felt that it was a reciprocated feeling, too. Because, he always used to tease me about how he chose to leave all the other girls and spend time with me, he likes to show his attention to me in front of our friends, he blocks my way sometimes and stares into my face until I turn red and he knows when I'm down and always gives me his time. However, very recently, he told me that he doesn't want to get attached to anyone after his sister and that's why he tends to push people away sometimes, I told him I understood that. Again, he kept telling me that his mum would love for him to get married and get her a grand-daughter but then he thinks it's better for him to be alone because he's a

To continue: he's a "complicated" personality and he's gone through much and he doesn't want to get any more closer to me because he's afraid that he'd be selfish and unkind to me and I'm the only one whom he treats with such care and wouldn't like for that to change. On the contrary, he always throws hints at me that he'd love to take a serious step in our relationship like joking about meeting my dad, talks about how he'll introduce me to his family in our "wedding" and such things. DESPITE ALL THAT, he's never admitted to me ANYTHING. People view us as a couple and we both know it but I feel like he's still afraid. He's considering studying abroad next year but is still confused because he wants better chances of education but still wants to stay around his loved ones. I don't know what will happen to us if he leaves. Shall we talk about our relationship honestly before he leaves? I personally would love for him to stay but I can't influence his decision because that will be selfish, very selfish of me. Do you think if we spoke honestly with each other about our feelings, things will be easier for us? Maybe he'd decide to stay or at least he'd know that I'd wait for him as long as it takes?