There is a good book I can recommend about alienation between parents and children. It is called "Divorce Poison" by Dr Richard Warshak. There is great advice about how to overcome and deal with alienation and separation, regardless of whether it is divorce-related or not. He also has a website with similar helpful resources. I found his book very helpful in the relationship with my own kids. https://www.warshak.com/ I hope this will be helpful.