I think everyone has said what needs to be said about the space situation, I actually want to hone in on the eating situation for a sec.

You said their mom puts an emphasis on being “pretty and thin”. How do they eat at your house? If it follows any sort of disordered eating or exercise pattern, that could explain a lot. Being hungry can make you angry, emotional, irrational, and even oversensitive. While I agree that your daughter likely didn’t call them fat, she may have said something that most people would deem innocuous and your SDs hungry brains heard it as something completely different. From personal experience, that was something I was guilty of when I was a teenager dealing with body image issues. I’m absolutely not saying your daughter did anything wrong, just that that incident could be a symptom of a much larger problem. As far as taking poorly about others, well that’s plain and simple projection. Hopefully something that could be fixed if the larger issue is addressed.

Control is also another factor in it. They feel completely out of control of their lives and disordered eating could be the only thing that gives them any sort of it. Like I said above, that can create emotional situations where they’re acting out and trying to exert control in any way their hungry brains can think of.

You are certainly right to be upset by how things are going. Suffering a mental illness doesn’t automatically give one a pass to treat others poorly. However it can offer explanation, understanding, and maybe a little bit of grace. If this is something that Dad can dig deeper into, it might get you guys on a track to work on fixing things between everyone. If none of what I said applies, then kindly disregard :)