Welcome to GN Marg there are several estranged parents and GP's here who will understand what you're going through.
A welcome to you too Sabanilas. It's great that you've found this site to share with others who are going through the same as you.
It as as you say, described as a living bereavement and that's exactly what it is. We grieve for the adult child we have lost, and often GC too. Our process of grieving is just as it would be if we'd lost them due to bereavement.
The first thing we experience is shock, often followed by anger that this could happen to us, that they could treat us this way. Then comes the pain. The pain of losing what we once had and having lost what we thought we would have, especially when GC are involved.
With time, for some of us comes acceptance. That doesn't get rid of the anger or the pain but it does enable us to move on and rebuild our lives.
There is life after estrangement. Peace and happiness can be found with time.
We've been estranged from our youngest son and only GC for 7.5 years, and for most of that time I've been here on GN, receiving support and comfort from others living the same nightmare as well as those with no personal experience.
I too was shocked, but also found some comfort in discovering just how common this is Sabanilas. When it first happens, you think you're the only one, that people will judge you and see the fault as being yours. Some do unfortunately but you begin to realise that if and when they do, the fault lies with them and not you.
There is a thread on this forum 'Support for all those living with estrangement' where the majority of us who are estranged post on a regular basis.
You'll be most welcome there, as you are here.
I hope you both post again as I'm certain you'll find the care and support and I and many others have found here on GN over the years.
Take care.