What are your ages?
Where do you know him from?
Do you call and talk to him?
Are you saying you like him?
First let me tell you, you can't ever know what another person is really thinking. You can only know what they tell you they are thinking. Whenever we fall in love, we take the chance that our hearts will get broken, thats just a fact of life.
It seems like he's given you every hint that he likes you and certainly wants to be more than just friends with you, so you have to decide if you want to move forward in this direction or if you want to keep it at just friends. His anger and rudeness could be because he feels like you rejected him and can't figure out why.
I would suggest talking to him and telling him that you were too scared to get involved because you value him so much as a friend that you didn't want to do anything to ruin that. Tell him that you would be willing to talk about it and maybe go on a date and see what happens from there. If he agrees then do just that, go on a date, spend some time together, do not rush into a relationship and certainly do not rush the intimacy. The longer you can hold off on a relationship commitment and intimacy the better chance you will have to get to know each other as potential mates rather than just friends.
I welcome your thoughts, let me know if you want to talk more
So...at this point, what is your question?
Its not unusual for a guy to use 'what if', its a way for him to know if you are interested without putting himself out there.