What should I do when i think my friend (15) is being encouraged to drink alcohol by her family?

My friend got drunk last night and the way she gets on about alcohol is disgusting. She keeps drinking around her family which is better than drinking out in public on her own or with friends I suppose. But that’s not my point. She keeps getting drunk every time she drinks alcohol that her family gives her. Either she is a lightweight person (if that’s what that is) or her family encourages her to drink. She told me one time that a family friend kept giving her alcohol to the point she got drunk, and her mum who was present didn’t do anything.

She keeps posting on her story these stupid Instagram reels about loving alcohol, and it’s pathetic, her family is pathetic. She’s genuinely enjoys alcohol and loves to flex that off, which i hate about teenagers nowadays.

Idk what to do, ik some will says lots of teenagers drink (which shouldn’t be normalised, stop normalising that please) but it’s the fact it’s her FAMILY THAT’S ALLOWING THAT, THEY ARE IRRESPONSIBLE!It’s dangerous. I just don’t want my friend to develop any sort of problems due to alcohol, so please if anyone can give me any advice that’ll be much appreciated.