code: public function deleteChild($id, $relation, $idChild)
      {
          $parent = $this->model->find($id);
          
          if (! $parent) {
              return null;
          }
          
          $resource = $parent->$relation()->find($idChild);
          
          if (! $resource) {
              return null;
          }
          
          return $resource->delete();
      }
docs: Delete Child
  
  @return boolean;