This was supposedly a seedy, run down trailer park which makes the situation more sad, because I have no idea why there weren't other relatives Christopher could not stay with. You will find that in some trailer parks, you are not doing to find the classiest of people especially ones that live in a delapitated trailer.
Given that Christophers father is a sex offender and that the paternal grandparent had custody, this suprises me. She could have always allowed contact with her son who probably didn't have visitation rights.