Madeleine and Brooke Astor

What was Madeleine and Brooke Astor's relationship like? Were they friends or did they not know each other very well? Did Madeleine go to Brooke and Vincent's wedding?
I may be wrong (other board members can correct me if I am) but I'm not sure that Madeleine Force Astor and Brooke Astor maintained any kind of relationship at all. In fact, I doubt that the two women ever even met. Brooke and Vincent did not marry until 1953 and, by that time, Madeleine had been dead for thirteen years.

Vincent did not get on well with his stepmother - who, famously, was even younger than him - and I gather they became almost totally estranged in the years following the 'Titanic' disaster. According to contemporary press reports, Madeleine (although invited) did not attend Vincent's wedding to Helen Dinsmore Huntingdon in early 1914, as she was holidaying in Virginia at the time. This doesn't suggest a degree of closeness!
Society circles in America are very small - my own research has revealed that the first-class 'community' aboard the 'Titanic' was in fact a tiny one, with multiple overlaps between the various passengers. It is quite possible, therefore, that Brooke and Madeleine met at some point in the years PRIOR to the former's marriage to Vincent Astor...