Hi SpanielNanny. We've been estranged from our son and only GC for more than 8 years now and my advice to you, to support your friend is to simply listen and be there for her.
It's called a living bereavement and the process of grieving is much the same as it is for a death. Shock, followed by denial and anger before eventual acceptance that there's nothing you can do to change it.
Your friend could look at the 'support for those living with estrangement' thread and that may lead her to joining GN enabling her to receive support, understanding and I hope some comfort.
For me, it was the listening ear of friends and their shoulders to cry on that I needed and joining GN, and realising that we were not alone in our experience and suffering was an enormous benefit.
I highly recommend a book by Sharon Ann Wildey called 'Abandoned Parents: The devils' dilemma'. It is far an away the bet book I've ever read on this subject.
It's not an easy read but for me, I felt as if she'd been sitting on my shoulder for the first 2 years of our estrangement as her insight due to her personal experience, and the research she has done is remarkable.
I'm so very sorry that your friend is going through this. It's absolutely heartbreaking.