It was told me a proverb from Lebanon not a long time ago: "Brothers are wings" i.e. they make you fly.
Well, it's true.

well, I have a sister but sometimes it's not this movie. I remember there often be some quarrel when we lived together and were smaller in age.

Though there is one saying in Bulgaria which sounds like:

"A brother does not feed his other brother but poor are those that doesn't have one"

so here I agree that sibling relationships are very important.

My brother and me are twins. It's different. I have ever wonder whether I will survive if I live without him and I tried.

I wonder if we can go for Astrology here, since you are almost in perfect harmony due to your time of birth and his

You also lived and grew up together at one age while my sister is elder she was already "in power" of parent's attention..this makes some difference too

You seem to be a lucky siblings couple

i don't know about the astrology.
yes, we are lucky and i can say that too lucky