I want to respawn a Boss prefab when its destroyed, but it isnt working.

Spawner script. using System.Collections; using System.Collections.Generic; using System.Runtime.InteropServices; using UnityEngine;

public class BossSpawner : MonoBehaviour {

 //to restrict the window of spawming
 public float minY = -4.3f;
 public float maxY = 4.3f;
 public float maxX = 6.84f;

 //to store enemy ship
 public GameObject bossPrefab;

 public float spawnDelay = 150f;
 public float spawnDelay1 = 155f;
 public float currentDelay;
 public float randomDelay;

 public bool isDestroyed = false;
 public int curent;

 public int totalSpawns = 16;
 public int currentSpawns = 0;
 public int count;

 // Start is called before the first frame update
 public void Start()
 {
     currentSpawns += count;
     randomDelay = Random.Range(spawnDelay, spawnDelay1);
     currentDelay = randomDelay;
     Invoke("spawner", currentDelay);
     Invoke("cancelSpawner", 1);
 }

 public void Update()
 {
     Invoke("cancelSpawner", 1f);
     Invoke("stopSpawning", 3f);
 }

 public void spawner()
 {

     if (currentDelay >= randomDelay)
     {
         Vector3 temp = transform.position;
         Instantiate(bossPrefab, temp, Quaternion.Euler(0f, 0f, 90f));
     }
     Invoke("spawner", currentDelay);
     count++;
     currentDelay += Time.deltaTime;

     /*
     if (Boss.isDestroyed == true)
     {
         Vector3 temp = transform.position;
         Instantiate(bossPrefab, temp, Quaternion.Euler(0f, 0f, 90f));
         Invoke("spawner", 1);
         Boss.isDestroyed = false;
     }
     */

 }

 public void cancelSpawner()
 {
     if(Boss.isDestroyed == true)
     {
         Vector3 temp = transform.position;
         Instantiate(bossPrefab, temp, Quaternion.Euler(0f, 0f, 90f));
         Invoke("cancelSpawner", 1);
         Invoke("spawner", 1);
         Boss.isDestroyed = false;
     }
     Invoke("cancelSpawner", 1);
     Boss.isDestroyed = false;
 }

 public void stopSpawning()
 {
     if(currentSpawns >= totalSpawns)
     {
         //stop game and play a cutscene
         CancelInvoke("spawner");
         Debug.Log("You Won");
     }
 }

}

Boss Script using System.Collections; using System.Collections.Generic; using UnityEngine;

public class Boss : MonoBehaviour { public float speed = 3f; public bool canShoot = false; public bool canMove = true; public Transform attackPoitn1; public Transform attackPoint2; public GameObject bossBullet; private Animator anim;

 //to keep health
 public int maxHealth = 50;
 public int currentHealth;

 //to spawn boss after a certain score
 public int maxScore = 40;
 public int currentScore;

 public static bool isDestroyed = false;

 public float maxX = 6.84f;



 void Awake()
 {
     //to get audio source and animator
     anim = GetComponent<Animator>();
 }




 // Start is called before the first frame update
 void Start()
 {
     /*
     GameObject theBoss = GameObject.FindWithTag("Boss1");
     BossSpawner bsSpnr = theBoss.GetComponent<BossSpawner>();
     isDestroy = bsSpnr.isDestroyed;
     */
     currentScore = maxScore;
     currentHealth = maxHealth;
     Rigidbody2D rb2d = GetComponent<Rigidbody2D>();

     if (canShoot)
         Invoke("bossShoot", Random.Range(0f, 0.5f));

 }//start

 // Update is called once per frame
 void Update()
 {
     moveBoss();
 }//update

 void moveBoss()
 {
     if (canMove)
     {
         Vector3 temp = transform.position;
         temp.x -= speed * Time.deltaTime;
         transform.position = temp;
         if (temp.x < maxX)
             temp.x = maxX;
         transform.position = temp;
     }

 }//moveBoss

 void bossShoot()
 {
     GameObject bullet = Instantiate(bossBullet, attackPoitn1.position, Quaternion.identity);
     bullet.GetComponent<BossBullet>().isBossBullet = true;

     GameObject bullet1 = Instantiate(bossBullet, attackPoint2.position, Quaternion.identity);
     bullet1.GetComponent<BossBullet>().isBossBullet = true;

     if (canShoot)
         Invoke("bossShoot", Random.Range(0f, 1f));
     SoundManager.PlaySound("BossShoot1");

     //to play bullet sound

 }//bossShoot

 void turnOffGameObject()
 {
     gameObject.SetActive(false);
 }

 void OnTriggerEnter2D(Collider2D target)
 {
     if(target.tag == "Bullet"|| target.tag == "Ship")
     {
         takeDamage(10);
     }
     
 }//trigger

 public void takeDamage(int damage)
 {
     currentHealth -= damage;
     if (currentHealth <= 0)
     {
         isDestroyed = true;
         if (isDestroyed == true)
         {
             canMove = false;
             if (canShoot)
             {
                 canShoot = false;
                 CancelInvoke("bossShoot");
             }
             SoundManager.PlaySound("bossExp");
             anim.Play("destroy");
             Destroy(gameObject);
             isDestroyed = false;
             //to play destroy animation and destroy sound
         }
     }
     //isDestroyed = false;

 }

}//class