you are being selfish. the best thing for him in this situation goes against what you want. if he is infatuated with you, you have to either ignore him and let him know that type of attention is unwanted, or as a previous poster said, just confront him directly when he displays unwanted behavior. it is NEVER best to beat around the bush. no one likes that.

you are misunderstanding things if you think the -both- of you have a 'sibling like relationship'. thats what you want, not what he wants. if you are sure that he wants you romantically, such a relationship will likely never satisfy him. depending on his personality type, he may never actually be able to shake his desire for you. you have to accept the possibility that the old relationship you had with him is no longer possible.