As far as how halfbloods were treated at the school that would be for you to decided. They were allowed to go, and if you post a topic in the sandbox you can meet other characters for your character to know. From there you can work out relationships. As far a what happened to her father that would be for you to decide, but they were placed in Azcaban, and released after the battle as in the books. If you wish for something else to happen then you can write that as far as being on the run and how it affected your character. Hope that helps.