@ernesjohnson My relationship with both of my siblings (2 older brothers) is mostly non-existent.
Both of them were my first (and longest-lasting) bullies in life; they basically always treated me like crap, no matter how many times my mother tried to encourage us to "get along."
One of my brothers I haven't spoken to since November of 2016. We had an argument over some differing points of view, and we just stopped talking. In January of 2019, our mother had a cardiac arrest and ended up in the hospital in a coma. I tried to reach out to this brother to tell him, and he wouldn't respond to my calls or texts. Contacted his best friend/roommate (we all grew up together, he knew our mom well, too; he had been considered one of my "brothers," he was like family), let him know what was going on and that my brother wasn't responding to me. He immediately went home to tell my brother about our mom; my brother still never called, never responded to any messages, nothing. Didnt go to the hospital to see out mom or anything. When our mother passed 8 days later, the friend contacted me with his condolences; brother still hasn't contacted me to this day.
My other brother (the oldest one) continued to treat me like shit on a regular basis all through adulthood. When I left my ex-husband and admitted to my family that he'd been abusive in multiple ways, both of my brothers called me a liar. But, my oldest brother was the most insistent that I was "making it all up." In fact, any time I've ever tried to talk about anything at all that is in any way bad or negative that happened to me, he always says I'm "making it up for attention" and then makes a bunch of insulting jokes about my circumstances or what I've been through.
Later, he told me it was harder for him than me to be a divorced single parent, because all I had to do was "spread my legs to get my bills paid." He literally said to my and my (now) husband's faces, like he was literally accusing me of only being with my husband for money; despite the fact he's never had much money (we used to both be broke together, then we both were making about the same, now I make more than 2x what my husband does...), and I've literally always been the only one of the two of us paying all the bills (which are and always have been in my name.) But, knowing/acknowledging that fact would ruin his ability to believe absolute bs about me, just so he can feel superior.
When our mom was in a coma, he came to see her, I think, once, maybe twice. I was there everyday, talking to the doctors, talking to my mom in the coma; my oldest brother had the power of attorney and he was supposed to be the one who made the decision about whether or not to "pull the plug," but he REFUSED to make the decision. Told me to make it. I'm 100% sure this was because he didn't want to have to live with having made the decision, but he was cool with me having to live with having made the decision.
He didn't start being any kind of nice to me, at all, until after our mother died in 2019. At which point, I was 35, and he was 40. And even then, his "niceness" just always feels perfunctory and forced. Like, he's only doing it because he believes it's what our mother would have wanted, but he's not GENUINELY nice to me. We hardly ever talk, I see him for a few hours at Christmas so my son can see his cousins. I feel awkward and out of place the entire visit, and happy when it's done.
Having siblings provides no guarantee of friendship. Not even of closeness.
I have one son, he is nearly 18 (will be in Nov.) He asked for siblings for a couple years when he was younger; but then when his dad actually started having kids with someone else, my son started to realize that having siblings wasn't really all he had thought it would be. After a while, he started saying he was happy I never had any more kids, because his siblings just drove him crazy when he was at his dad's, and he greatly preferred the peace and solitude he had when he'd come home to being the only kid in the house.
I think a lot of only children who long for a sibling are just thinking the grass must be greener on the other side. People have a tendency to assume that whatever they're missing out on would have 100% been a positive experience - because in all honesty, it's a "fantasy" scenario for them. No one fantasizes about things being shitty, you know? They never consider the very real possibility that their theoretical siblings could have been assholes they wouldn't have gotten along with, anyway.