调用嵌入式containerVC方法时未调用父VC委托方法

我有一个父VC,子VC嵌入到容器中。两个VCs都符合委托,但只调用子委托方法。如何让VC的两个委托方法都响应?我是否缺少容器视图的委托模式?提前感谢您的帮助。

中心类:

public protocol BLEManagerDelegate: class {
   func bLEManagerShowAlert(message: String)
}

public class BLEManager: NSObject {

  static let sharedInstance = BLEManager()
  weak var delegate: BLEManagerDelegate?

   public func postMessage() {
      delegate?.bLEManagerShowAlert(message: message)
   }
}

家长VC

class HomeVC: ContentViewController, BLEManagerDelegate {

    var bLEManager = BLEManager.sharedInstance 

    override func viewWillAppear(_ animated: Bool) {
        bLEManager.delegate = self
    }

    // delegate methods

    func bLEManagerShowAlert(message: String) {
    // THIS METHOD IS NOT GETTING CALLED
    }
}

嵌入到ParentVC中的容器视图

class ChildVC: UITableViewController, BLEManagerDelegate {

    var bLEManager = BLEManager.sharedInstance 

    override func viewWillAppear(_ animated: Bool) {
        bLEManager.delegate = self

    // delegate methods

    func bLEManagerShowAlert(message: String) {
    // This method IS getting called
    }
}