This is Maria no Danzai, but if the Mom was already insane.
That girl better not keep bullying her daughter. Else she's gonna be in a body bag
as a doting mother who 'punishes' herself for accidentally hurting her, , imagine the spiralling there'd be once she hits puberty and being like "mom i hate you, go die!" in a temper tantrum or so XD;
if she's not some total sociopath who knows and manipulates her mom on purpose, idk how she'd be a well adjusted adult in the working world or so if the mom does die due to illness or an accident versus her threatening her boss/superiors to treat her better if not somehow have a ton of money saved up for her to 'live comfortably after she's passed' or so but given they live in a run down apartment idk how likely that is (unless that's on purpose or so like 'we have shitty living conditions but i'll shower you with so much love you'll put up with it/only have me')