Honey I know what you mean about the validation. I think when you've been undermined so consistently and so profoundly, at your very core, every little bit of someone just understanding where you're coming from and recognising there's a truth in what you say is like gold dust.
My mother too lashes out like a demon when her world of denial is threatened. And regularly called me "melodramatic" when I was a child too young to understand what melodramatic even meant. So much easier than acknowledging that your child may actually be in a lot of emotional pain, and that you and your husband and favoured son might actually be the cause of that pain.
I too periodically struggle with the fact my son has no relationship with his grandparents on my side, that they don't know him at all, that they have never known me as a mother myself. It's shit. But then I look at what they did to me, and what they would have continued to do to me if I hadn't shut them out, and I know it was the only sane option, and I think I deserve to feel good about having had the courage to do it.
It is such a taboo though. I think that there's culturally still a huge bias towards the parents in dysfunctional families, unless the abuse is of the tabloid headline grabbing variety, and those of us who as adult children choose to walk away are often still perceived as cruel and selfish, needlessly hurting our poor, bewildered parents, who after all "did their best" and "loved" us "in their own way"... There is so much minimising that goes on.
Chilling, while it's really important to have the validation of others who've gone through similar, I find it's also really helpful in a different way to have the validation and understanding of those like you who didn't go through it themselves, but who get it anyway. It's a much needed counterbalance to the stuff I was taking about above! 
Finding it hard to get much time on MN atm, that'll be the half term effect then...
Wishing you joy of the property search, Honey. Step by step. My parents are at a considerable distance, and it does make it a lot easier.