Sorry it's been awhile since I stopped in on your thread. Just been catching up on this. Wow, sounds like things have been escalating here. If she is being physically abusive to your s12, I can only imagine what a difficult situation that puts you in. But if this is behavior that continues, I invite you to seriously consider contacting child welfare about this or taking steps to get the kids safe. That kind of behavior is no longer about MLC, it is about a drinking problem and abusive behavior. It's unacceptable and, if what your S12 is saying is true, it is child abuse.
This is a really tough situation, Tree. Only take the parts of what people are posting that work for you. This is my humble 2c worth.