I had a half-brother on my mother's side who was 8 years older than me...we only lived together for a short time when I was very young before he went to live with his dad. He passed away about 10 years ago from a brain tumor.
I had a half-brother and a half-sister on my dad's side who were older than me. I only remember meeting them once and I have no idea if they are still living or not.
I was raised mostly like an only child by my Grandma and step-Grandfather, until my Grandma died, forcing me to live with my mom after that.
I knew very little about my half-siblings.
I rather enjoyed living as an only child in my Grandma's care.