Lets say u have a child and he said he is hearing voices.. Wud u bring him to a psychiatrist/psychologist or call a shaman or those who deals with ghosts?
It is not normal to hear voices. You have to recognise that. Then it might depend on what exactly these voices are saying! In twenty odd years of social work. I've never yet met somebody who, when hearing voices, said they were being given recipes for bunt cake ! or being given instructions as to how to fix the car ! So diagnostic help from a doctor and then probably a psychiatrist before you go down the Shamen route.
You and the child should pray to GOD to help remove such voices from his life. It isn't humans that have solutions, it's by GOD'S grace that are problems are solved. Pray to GOD together and ask GOD to help him remove such voices from his life.