Dr. Joshua Coleman's discussion forum is a place that is particularly helpful for parents who are trying to come to grips with estrangements by their children.
At this time of year I know that many people are looking for support to get them through the holidays. I do recommend this discussion forum. It has been around for a few years but has gone through major improvements. It is much easier to use than it was a few years ago when it was one long window of over 1,000 posts.
Forum: When Parents Hurt: Dealing with Parental Alienation