I thought this was Teru trying to play babysitter at first due to the lack of black space, but it’s actually Mei and it shows how strikingly similar they are!
And they are still deliberately keeping their family situation and faces vague. They showed Teru in a flashback with her grandfather after their parents funeral (or was it Mei’s?), so there has to be a reason why Mei is living and raising Teru alone.
I’m still holding onto my genetically created clone theory, and seeing their home situation along with their similarities in appearance and personality is only reinforcing that!