A loving mother would not place duct tape on her child, even if an accident she would remove it and try to resuscitate her..and certainly wouldn't put it back on.
And a loving mother does not chloroform a child she loves. That's abuse...and Casey was an abusive mother regardless of her reasoning's why she did that.
Those two issues alone are critical in this case...Casey's actions surrounding her daughter are clearly abusive..and that enough to cause her death.
Also, with anyone else in that family, 911 would have been called if there had been an accident. Casey is the only one that wanted to get rid of her “problem”.