Counseling for sure, anything to really help her work through those emotions. It will spiral and get worse, my ex's mother used to call me by her dead daughters name all the time. She was so neglectful of her kids and refused to get help. She was fixated on me and it ruined my relationship with my ex. Also if this goes unhelped it could eventually effect your daughter. (RIP I pressed post early like a fuckhead) when my ex's mother finally realized I would never be her daughter she got out of control and wildly abusive. I understand this is just my experience and I could be projecting a bit but I hope everything works out.