Is there anything we can do to get her due justice since child got no proper representation?

My granddaughter (15) reported her stepfather to the police for sexually assaulting her. Of course, he denies it and the saddest part is that my daughter stood behind her man. With the stepfather and mother just in the next room. The police put the granddaughter in a room alone with just the officer and closed the door. Never told her that she had any rights to leave or anything. They just repeatedly accused her of lying over and over till she just couldn't take it any longer and told them to believe what they want. Then instead of further investigation, she was sent home that very same day with her stepfather who has since made her life hell. To add insult to injury of an innocent child, the police charged her with obstruction of an officer because according to them, she lied. She then went to court where her lawyer told her to plead no contest. She didn't know what that meant so she did. Of course her parents never bothered to make sure she did, since the stepfather was the accused and the wife stood by her man and not her daughter. As her grandparents, we were told by her lawyer that we weren't allowed in the courtroom. No one stood by her.