I'm the youngest of 6. There's 14 years between my eldest sibling and me.
I was 7 years old when my eldest brother emigrated to Australia, so I didn't have any sort of relationship with him. I've never been out to Australia to visit him, but he comes home to Scotland every five years or so.
Being honest, I find him insufferable. He's got some questionable views, and prides himself on his misogyny.
Obviously we're siblings, but I know nothing about him, and I find him utterly repellent.
My second oldest brother lives in the USA. We message each other occasionally, but we don't have a lot in common. He earns stupid money, and will say to me stuff like "Come over for a holiday!" - but I'm not in a financial position to do so. Despite earning a multiple six-figure salary, he has no concept of what life is like when you can't afford to pay for flights. He's never offered.
Sorry, italics - I'm not sure what I've done?
I have another couple of brothers living in the UK, who I'm reasonably close to. That said, our mother has been ill for the past 5 years, and neither one of them has stepped up to make anything of a contribution - so I'm feeling pretty resentful of both of them at the moment.
They like to text me asking for updates, but their actual tangible input has been next to nothing.
As for my sister, she's my absolute lifeline. We are the best of friends, and we could absolutely call on each other at any time of the day or night, no matter what.
It wasn't always thus - we fought like cat and dog as kids, and there were a couple of occasions as teens where we actually tried to murder each other.
But, she's the one person in my life who I can rely upon, and the same goes for her.