What does it mean when a deceased person appeared in someone’s dream?

I dreamt of my dad after he passed. I remember he was painting a sunset and I mentioned how amazing it was, we talked for a while. It really comforted me, I'd only got to know my dad properly the same year as I hadn't seen him since I was a young kid.

Anyway I told my mother about it and she told me she'd spoken to a medium weeks before and she told her that my dad had moved on and had started painting. There's no possible way I could have been influenced as she never told me. So I think there is a spiritual connection or other dimension/afterlife, she probably visited you.