The very idea is horrific, but it's more likely the child is seeking a parental figure in an adult and, if they are entering their pre-teen years, may exhibit pseudo-sexual thoughts and ideas that are not clear or organised well. In other words, child emotionally mixes sexual desire/ curiousity with want for an adult that will protect them and be kind to them. The child is afraid, lonely and at the same time, is becoming a teen.
It's best to provide moral support to the child and discourage their sexual desire/ curiousity as safely as possible. Certainly don't allow anything sexual to actually happen - not only immoral and evil, but also illegal.