Yea, to me it sounded more like someone who was close to you and somehow you two grew apart and became strangers to eachother. First thing that came to my mind was not an older brother though... more like a girlfriend or a wife
I think I like that the stranger remains anonymous, since it leaves a bit to the imagination of the reader/listener (I could really envision someone living with a wife he THOUGHT he knew), and don't think you should change the "stranger - like we always did" paradoxes, since this is exactly how you appear to have felt. I'd follow up on some of lc's advice on clarifying a little more about what happened between the two of you though. This leads more to the idea that the "stranger" is in fact not a stranger in the strict sense of the word as well...
I really like this one, hope you will put some music to it soon
