Brother-Sister

At school, in this country, at this sort of era, it seems to be common for youngsters like me to have a sort of "sibling relationship" with those unrelated to us, whether they be older or younger than us.
I don't have any, though. Since I don't associate well with anyone older or younger than me.
I feel uneasy calling Harrison abang and him calling me adik. He calls me adik for quite a while now, even though we don't think of each other as siblings.
I remember I once told him that I thought of him as an older brother. Two years ago, I had this attraction towards him, a wanting to be good friends and - if possible - to be able to call him my brother, since I've always wished I had an older brother when I was younger.
Last year, I realised why I thought of him that way; he was caring and protective like an older brother. He was also nice to hug; like a giant, lovable teddy bear. That's why my other nickname for him was teddy bear =3