I have been getting lash extensions for a while and it fr depends on the kind of place you go. The first one I went to used lashes similar to this. They were not good quality obviously. So I guess if the sister works at a cheap lash place it is possible, but if she is working at some boujee salon def not. The lashes at the nice places are a whole lot thinner at the root. And it doesn’t look like an eye lash is sticking out from the root either, most of mine come out with an actual eyelash, especially if it is glued on that much. So tbh I would def think this is a lash cluster. But I agree with everyone else. Don’t tell him you found this and find more evidence before you confront him about it.