OP, you’re getting downvoted a lot, and I need you to know that most of the people here don’t know what it’s like to have that type of relationship with their mother.

My biological mother similarly treated me closer to a friend than as their child, well it’s a long story, but CPS was called for a reason.

I don’t think the downvotes are warranted because these internet strangers don’t have enough context for your protection of sibling and yourself.

Op if you need someone to talk to, inbox is open

Good luck