Ok so my father has abused me before. He has left bruises. My friends older sister has considered adopting me or trying to gain temporary custody, until my father is easier to get along with. I was adopted at birth, and I'd feel bad leaving my grandparents and other family and such, but I can't stand my dad. Is it legal for my friends sister or mother to do this?

Not really, first you will have to get CPS involved and they will have to remove you from the home, They will try to fix issues in the home and return you to the home.

It will take lots of court action before adoption would even be possible.

What about temporary custody?

Same thing. Before anyone can take you from your father's custody they will have to go to court and prove your father is abusing you. Which also gets cps involved.

What if I just lived with them for like a week..

If your father wants to make trouble he can cite you as a runaway file against them for parental alienation. You need his permission to stay overnight with anyone else.

My mom is always the nicer one.. But she still agrees with him most of the time😓