Serious problem plz help?

[aethelbert35]

i have an friend who has an older ex gf, her ex is a psycho that's why they broke up but it seems like my friend is abusing drugs she keeps seeing her ex. every time i ask her to hang out she has an excuse like; she didn't sleep in 4 days or she has a migraine nd is throwing up. one time they got into a huge fight and her ex went to my friends house told her mother my friend is doing drugs her mom didnt do anything i want to get involved. her mother wont help then ill get the law involved since i know her ex sells drugs prescribed to her. please help i have no idea who to ask for help