Optimistically, you tell yourself 'No one is THAT stupid.'

"..drugs and alcohol were ruled out.."

Dammit. =(

On a serious note, hopefully she'll be required to take a parenting class so she can understand the harm she could have and may have done to her children. 

To be fair, not everyone is born with those protective parental instincts. Some people need a little education. 

I wish her and her children the best.