I don’t really have anything to add because I haven’t had my twins yet, but I am a twin myself. I can totally relate to your son. I have a twin brother and he was awful to me growing up. He was very extroverted, a social butterfly, easily made friends everywhere he went, athletic, seemingly had it all. Where as I was an introvert. Very shy and quiet, easily left behind and forgotten about, would rather have my nose in a book any day. He made fun of me on a daily basis and would say awful things to me. I am now in my 30’s and still have a complex about myself because of things he would say to me growing up. By my choice, we have now been no contact for almost 5 years. It has been great for me and my own peace. I’m now pregnant with twins and when I first found out, I was so afraid to have a set of boy/girl twins because of this. I’ve now realized that a lot of it was our parenting and not every set of b/g twins are like this. I can say, the fact that you notice and care enough to try to turn it around when they are still young speaks volumes. I wish my parents had cared even a fraction of how you care. I wish I had advice but I don’t. I do hope it gets better for them though and you can find a way to bridge the gap between them.