I have seven siblings, and have varying relationships with them all. For the most part, though, we're all pretty close.

My long-time beta, Nyx Ro, claims she doesn't "see" the sibling thing, but admits she's not close to her siblings.

She once challenged me--and it's still in my WiP folder--to write a CONVINCING story in which Sam and Daniel were actually siblings--possibly even fraternal twins--and one, the other, or both had been adopted.