Five year difference between my two boys. At one point there was a bit of "he can't read that...it is my book and he is 5 years younger" (which sort of meant that if the "baby" could read it then he, the big boy, was reading "baby books"). That was a short lived phase because then he realized he had a built in confederate to discus his much beloved books and at a deep level (not like kids at school).
And really we have set limits with the younger with some of the dystopia genre books (no need to read that stuff at age 7 even if you can)...and what is a good limit if not to be broken (or bent), but I digress.
I will say that if you fast forward to age 10 and 15 there are good moments and bad moments but the good does rule mostly. And they do move on to separate lives with different stuff to do. I think it is hard to live with anyone for years and never bicker. For my two it is nice to have a brother who is an intellectual peer. And the love is there even if the 15 year old isn't as demonstrative anymore about it.
My younger brother (one year) and I fought like you couldn't imagine. He is PG and I am (don't know exactly but definitely) not-PG and we always were competing for the same things: Keys to the car, attention, prize, last piece of cake, whatever. But now as adults he is so quick to say how much he does love me. He turned out to be an awesome adult and I am lucky to have him.
