I would ask if I could help more with the household so I could have a place where my comments might hold more weight.
It sounds like a sibling rivalry situation with your friend being the "mom" to both of you and you and the daughter complaining about each other. I would either take a responsible position in the household or pay better attention to negative situations and counter the daughter's known responses with threats of my own such as, "If you mention this to your mother, I imagine I can get her drug searches to be a lot more intense in the future."