Esmay is quite right in mentioning the Inheritance Act. Whatever case it was determined on is irrelevant as the IA is often used to contest a will. People do have to be so careful especially as there are so many second marriages and step children to consider which I am sure you all are aware of. My view on disinheriting your EAC is to leave an equal share. My own mother cut my Estranged half sisters out of her will, but I put that right by giving their shares to their children. They were so relieved and I was glad they accepted it. I also have an ES who has serious mental health issues. Despite the issues, I have been in a fortunate position to give both my son's a substantial amount 3 years ago and I gave them both an equal share. For me that was more important than worrying whether the now ES would squander it. The stakes were high believe me, but he used it to study law and did amazing despite everything. We have done our best that we can for him emotionally too but sadly he isn't well again. Neither of them will get anything else until we pass away, but they will always know how much they are loved by us. I'm sure all EP's have gone through terrible pain and still hurting as much as our EAC, but we love them unconditionally or we should do. A will, if we have money left, is the final act we can do for them, regardless of whether we are estranged or not. Money isn't everything, but it sure helps. I want to leave this planet knowing that I did everything that's feasable to help my kids one way or another. It's the thought that counts and a last act of kindness we show them.
By all means help the AC that isn't estranged whilst you are living, it's your money to spend as you wish. That's something I do too, but I keep a mental note, and make sure that if my EC needed help in the future, they would get the same regardless of whether we are estranged or not. He still lives on what we gave him and doesn't claim benefits as far as I know. Not everyone will agree on this thread, but whatever the reason for the estrangement, and whether we perceive it as beyond cruel, I personally don't agree that we all do what's right for us. I think we do what's right for them too!