my suggestion to you is to step it up
when he asks them questions about scrubs
you answer it with a reply that you know will be informative yet funny
he knows you like him
but doesnt want to hurt your feelings
but he cares about you cuz your his friend's sis
that's why he sez hi and gets you food
I think you have to be yourself, don't be shy and just be cool about it all
don't have high hopes or anything
just crack more jokes and be more outgoing but stay true to yourself
don't go to extremes to impress him
He sees you as his friend's sis
I think you should really try to move on
he sees you as a younger person too