I have a brother. He's two years younger than me. We're both on the spectrum, which, I'm sure, affects how we interact.
When we were little, we were best friends and totally inseparable. He had a really severe speech delay and I was the only one who could understand him (I even did better than my mom and she understood most of what he said), so I became his interpreter at an early age. I never minded that, though. We moved when I was 8 and had *no* friends in the new town. There's a lot of prejudice there, so we didn't have much chance to make them, either. We just stuck together and were happy. Then I made one friend, who felt that younger siblings were evil and meant to be abused. She drove a wedge between my brother and me. Now, as adults, our relationship is pretty solid again, but not like it was as kids. He's very selfish and can't see beyond his obsessions, so if I can't fit within the current obsession, I don't exist. Right now his obsessions are finding a girlfriend and movies/shows that I don't watch. I tried to start watching one of the shows, but I couldn't keep up with it, so I'm mostly ignored. Mostly, it's just that he really doesn't know how to do normal social interactions, so I don't stress about it. There are things he does that, for him, are the equivalent of saying he loves me. Others don't see it that way, but that's what it is. Like, he sent me home with a movie last week. No one touches his videos. Ever. But he loaned one to me. (When we were both living at home, on the rare occasions I was allowed to watch his stuff, he put it in and took it out when I was done to "protect" it.)
So, do we have the perfect sibling relationship of movies? No way. Are we friends who love and support each other? Absolutely. Most of my relationships look a little different than the norm. A large portion of my family is not NT, though not all have ASD. There's a wide range of variance between us all. I only have a couple friends, if you don't count relatives, and they seem to adapt to how I interact pretty easily.