Sympathy for your son and for you, and the children in the middle of this tension. Maxgran's question about what you may have done to make her dislike you so much may be helpful, it may not. The reality is that some people are 'difficult" and when one of those people is part of your family, well, life becomes difficult. I agree with others who suggest your son gets some professional help. His GP may be a good place to start as they usually have lists of local groups or individual counsellors that may help him. He must be so anxious. Controlling, manipulative individuals are very difficult to help, and living with these people is extremely stressful for everyone. You could also seek some support, either from a trained counsellor, or via your GP. The only thing you can change in this situation is your response to it. Best of luck.