Your house your rules! Start laying down the law and if your cousin has anything to say about it tell her she can find somewhere else to stay
You need to check both of them. There in your house and your daughter should not have to go through that mess in her on house. You nor your babies need that kind of stress. Good luck!
Speak up and tell the mother and also tell the child to quit tattle telling and bossing your daughter around. Be serious and stern.. if your cousin don't speak up and keep her in line I would! They are staying in your home with you under your roof. If you were at there house it might be a lil different but I would not put up with that!! How far along pregnant are you?
U need to talk to your cousin before things get out of hand. Tell her how you feel and what needs to change.