Family trouble?

i am in complete shock right now and so is my dad, well practically my whole family... last night my dad almost suffered a near heart attack and had severe chest pain because he was worried about my sister, where she was, she didn't even come back and it was almost 10 pm... when he called and said everything he wasn't feeling good please come home, she thought her friend was way more important than her own father so she spent the night at her house, she was suppose to do paper work yesterday at Tillys coz she got a job there and she made it seem it took all day when it didn't. She is also hiding a bf behind my dad's back, turns out she was at the movies with him last night between the hrs of 6-8 pm at the same time my dad was calling her and this guy lives 100 miles away from us. I m really pissed off and feel sorry for my dad because my sister is putting our whole family in jeopardy, she doesn't listen to any of us she's going towards bad company... what should i do as a brother