Has your daughter gone to any pre-natal/parenting/Lamaze classes?
As you have mentioned, the volatility of her emotional state makes you worry for this child.
What will you do when she is home alone with this child, and you are at work?
I have a friend who had to report her daughter to DCFS for slapping her baby to get her to
stop crying. She took pictures of red marks and bruises on the baby. Hardest thing she ever
had to do, but for the sake of the child, she had no choice.
Luckily, the baby was placed in a wonderful foster home, and the foster parents
are working through the process of adoption now. They've had her granddaughter
for 3 years, and she does get to see her.
