How to help a friend in dire need of help?

My friend's dad has melanoma, skin cancer if you didn't know, and he's literally dying right infront of her. She takes pills to forget about stuff and throws up because of them, she cuts her arms and burns them too. What the **** do I do? We've been best friends since 3rd grade and obviously I don't exactly know what shes going through. Therapy isn't an option. We'll have sleep overs and she'll drive home at 2 in the morning because she's too upset and doesn't want to 'ruin' my night.. We're both 17.