Hello!
I have one DS (who I am close with) and one DB (who I am not close with at all). My experience of having a brother has actually been pretty rubbish.
I have one DD and am expecting a DS this summer. We won't have any more. I am personally excited to have one of each DC, but it's made me reflect on my relationships with my own siblings a bit. I have a good frame of reference for a close sister/sister relationship, but not a brother/sister one.
To offset my experience, I would love to hear about your positive experiences of adult brother/sister relationships - do you communicate often, spend time together, know each others kids, rely on each other, support one another with your parents etc?? These are all things I hope for them (though I realise there are no guarantees with any siblings!).
Thank you :)