Most Helpful Guy
i suggest you ask his friends about, does he have any feelings for you.
Most Helpful Girl
Just do it. Even if he does call you sister that doesn't mean anything. I actually think it's better to date someone you're friends with first because then it's easier and just better. And trust me if you guys break up it won't be THAT weird to the point where you can't talk to them. Just go for it, because it's better than just bottling up your feelings and not trying at all.