I'm scared for my future children just a little bit. I want then to be able to put on any shoe they want on first!
My children's relationship is nothing at all like mine was with my siblings, nor anything like dh's with his cousins (he's an only, but a huge, close extended family).
It wasn't an accident.
I suggest tracking down a copy of The Winning Family by Louise Hart.
It seems like they are set in their ways and that is how they were raised and who they are. Just like everyone else has been raised and are comfortable with it. You def need to decide if this is something you can live with. If you already have children together sit down and talk about how you both want to raise your child and what are the things you agree with that he does and things that bother you and let him do they same. You have to communicate to get things resolved. Hope everything works out.