do i get banned for using stockfish against my friends in a friendly game?
You can. In an unrated game when your friend knows you are using an engine and allowed it then it would be ok, though that permission wouldn't be something staff would be aware of, so is still risky.
https://support.chess.com/article/648-what-do-i-need-to-know-about-fair-play-on-chess-com
do i get banned for using stockfish against my friends in a friendly game?