Smack her on the ass and put her to bed each and every time she abuses the dog.  When she cries, ask her how she feels.  Then ask her how she thinks the dog feels. Lather, rinse, repeat.  She will learn eventually.  Pavlov's dog learned that a bell meant food and the slobbering commenced.  This kid will learn that abusing the dog will result in a stinging butt and boring isolation.

This kid needs to learn that to continue her crappy behavioral choices is choosing to live her life with her nose in a corner for hours and hours on end and sitting in an isolated area writing thousands upon thousands of sentences that highlight her crappy behavioral choices.  All in perfect handwriting, perfect grammer, and with perfect spelling.

No one will likely ever get through to this kid. The best hope is that eventually she will mature to the point where her toxic choices are minimized enough that she is less of a curse on your life, the life of your partner and the lives of anyone else she infects with her presence.

I understand that she has developmental issues, she comes from a genepool rife with mental illness, and that she is a child.  She still should not be allowed to ruin the lives of anyone else.  including the dog.

IMHO of course.

Good luck,

Do not disengage when it comes to the dog. You need to protect the dog, and if you can't, you need to find him a new home.

I think she sounds like a brat who should be kicked out of your home, but the number one issue here is how she treats the dog. Unacceptable and she should be severely punished for that. Never leave her alone with the dog. And I disagree about finding an elderly dog a new home - that is cruel - how can anyone abandon a dog like that? The POS SD needs to go not the dog. 

Is she sociopathic?  

The most common sociopathic symptoms in children are as follows:  Stealing, Vandalism, Manipulation, Hyperactivity, Speech problems, Compulsive lying, Learning disorder, Cruelty to animals, Dislike and anger towards authority, Problems with retaining peer relationships, Consistent bedwetting after the age of five, and Reckless disregard for safety of self or others.  They can also be confidant, intelligent, charismatic and persuasive of others as well as themselves.

I wouldn't usually, especially in a blog, just whip out this question about a child, but the animal abuse is what gnaws at me.  And, it is a big red flag, along with the bedwetting.

A commonly asked question is “Can sociopathy in children be cured?” Although it can be quite difficult and may need a lot of time and patience, research shows that there are a number of effective treatments for this disorder. It’s often observed that parents of these kids tend to avoid dealing with sociopathy in their children, often dismissing the problem as mere rebellion. Parental support and constant adult supervision is very important and effective in avoiding such tendencies in children.  This is from: https://psychologenie.com/sociopathic-behavior-in-children