Heh, yeah that'd work! She gets curious because of one of the random trinkets she sees in the window and it all goes from there.

I feel like a lot of people at this rate are keeping an eye on her so he wouldn't be the only one at least. But aw honorary sister would be cute, yes. And her actual bro would probably be relieved if he knew others were keeping an eye on her while he is out at lectures/work and all.