froggie wrote:
 It is not just to do with broken and difficult relationships for us with our children, but the effect of the madness on the relationships of our children with each other. Personally I think it is a mum thing. The cords that tie us to our children are strong, siblings do not have such a strong tie. I think that we never can let our children go, not really and hope always exists.

Thank you froggie - this has been very helpful for me.
I've been feeling angry and hurt - as you say, not just for me, but for the broken relationship between my children, imagining that they are hurting as much as I am.
Your observation that feelings between siblings are not necessarily as strong as the feelings between mother and child was a lightbulb moment for me - and has made me feel much better.
I have three sisters, two of whom I very rarely speak to simply because we live in different parts of the world and have very little in common (besides my mom - and we get each other's news via her), but it doesn't mean we don't care - we are simply living our own lives.

As Whytebyrd says, it's good to be able to share our feelings with other mothers who understand - thank you.