DSis and I have fallen out, it has been two and a half years. In my view (and the view of DH, mum and friends I've spoken to, and mumsnet previously), she was completely in the wrong. It is clear that she would like to reconcile - by this, she means, we go back to how we were before and carry on. She will not acknowledge she did anything wrong, will not apologise, just thinks everything is my opinion, my perspective, my view and that she has her own (which don't align with reality, or that there's an objectively unacceptable way to treat people).
I love and miss her. Our brothers live abroad, parents are divorced and mum has recently been diagnosed with cancer. I feel as though this needs to be fixed but don't know how to stimulate any change in her. How should I proceed without going back to being treated poorly?