Getting Emancipation or Custody of a Sibling

My question involves emancipation laws for the State of: Iowa

My sister is 14, and her father is going to a half-way house for three months, in which she'll have to stay with her grandparents. Her father is an alcoholic, and he currently has an ankle-bracelet, and he's on federal probation because of his drinking problem and posession of firearm. My sister is ready to run away, and I'm trying my best to get her legally away before that happens. I realize that Iowa doesn't have a 'statute' for emancipation, but when I'm 18, can I get custody of her as a sibling? I can help provide for her, along with having housing and getting her to a school. Is there any way I can make this work?:confused:
Thank you very much
Desperate Older Sister

Where is Mom?