Best friend drama?

So I have three best friends, right? My bestest best friend, Mandy, I have known since Kindergarten. My bester friend, Olga, I have known since 6th grade. And my best friend, Dani, I've known since last year. The problem is we all just graduated [except for Dani she's a 6th grade and we're all 8th graders]. And Olga goes to a new school and she's started smoking. Dani is still at our old school and is smoking pot. There's nothing really wrong with Mandy but Dani introduced her to some friends and Dani told her to give them head. They all have drama and sh*t. What do I do? Tell them everything they do it bad? Or just chill it out?