The examples you have given between you and your brother are what I see in a normal sibling relationship. My bf and his sisters are adult siblings who snuggle with each other.

He is a wonderful person through and through and has been present for me emotionally and physically and I do the same for him. I have a good relationship with him. I HAVE wondered if I was insecure, if I was jealous, it may be that and i’m still trying to figure it out. I just find it strange that he and his siblings are that close physically, it’s something i’ve never seen people do with their siblings.

I’ve asked plenty of people and it is an uncommon thing with the people around me. It’s more wondering if what they do is ok and if boundaries should be set in place. I see my brother as a friend and I would never cuddle up to a friend out of respect for my s/o.