Golly @Thebeachismyhappyplace, apart from a few tweaks you could be writing about my relationship with my brother. It is so familiar to me as my own 'D'B is a horrible bully, who seemingly takes great joy in insulting & humiliating me when we (thankfully) rarely meet at Christmas. Well done on going NC, it's a hard decision to make (or it was for me) but it's the right one, to protect your mental health. Good for you.
I think my situation was down to my DPs very toxic divorce in our early teens & resulting fall out. I've decided to go LC (at least) for now, and it's cutting me up inside because it likely means I'll never meet my recently arrived DN. I'm unlikely to have kids of my own, have an 'auntie' to many of my friends kids (my bedtime story reading skills have been requested on several occasions!), and it upsets me to think I won't be able to be around for my actual niece. That said, maybe it's for the best. After bouts of depression, anxiety and then years of therapy to rebuild myself I've realised it's too damaging for my mental health & self esteem to be around him. Plus I wouldn't want her to grow up seeing that behaviour towards anyone and thinking it's acceptable or normal because her dad does it. Apparently fatherhood is 'softening him' according to my DPs, though I'm yet to see the evidence.
I'm lucky, after many years of his bullying behaviour, my parents recognise that my withdrawing is for the best for me & support me in standing up to him in that way. I know they both feel incredibly guilty for enabling his behaviour for the last 25 years, especially during their divorce fallout. It's just a really sad situation all round. I see friends & family who have great relationships with their siblings, and wish that were the case in our family. Alas it's not.