Error referencing custom class elements

Hello everyone.

I've been working in a grid based project in which I save an instance of the class "Cell" in a "grid[ , ]" array, that represents each particular cell of the grid and conteins information about it, including a reference to the character in it. The problem is that, if I try to modify the stats of that character nothing happens in the game, but the methods of the class are called, as if I was accesing a copy of the character. I've tried fixing this passing the character and the cell by reference, but still not working, and as I have read, pointers in C# are not the best option, so, any idea on how I could fix this? Thanks.

This is where I try to modify the stats:

 void ReplaceForWall(ref Cell cell){
   cell.FreeCell();
   bool combined = false;

   Vector2Int pos = cell.gridPositionNormalized;
   int playerMod = (xScale == 1) ? 1 : -1;

   // Vemos si en la siguiente casilla tiene otro muro
   if( (pos.x < grid.GetLength(0)-1 && xScale == 1) || (pos.x>0 && xScale == -1) ){
     Character posibleWall = grid[pos.x+playerMod, pos.y].host;
     if(posibleWall != null){
       if(posibleWall.alias == "Wall"){
         posibleWall.maxHealth += posibleWall.maxHealth;
         posibleWall.Heal(posibleWall.maxHealth);
         combined = true;
       }
     }
   }

   if(!combined){
     Character instance = Instantiate(Wall, cell.worldPosition, Quaternion.identity);
     InitInstance(ref instance, ref cell);
   }
 }

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class Character : MonoBehaviour
 {
   public string alias;
   public int maxHealth;
   public  int currentHealth;
   public int waitTurn;
   public int damage;
   public int size;
   public int id;
   public Cell cell;
   public Text HUB_Health;
 
 
 
   void Start(){
     currentHealth = maxHealth;
     HUB_Health.text = currentHealth.ToString();
   }
 
   public virtual void Attack(){
     Debug.Log(alias + "is attacking");
   }
 
   public void Heal(int hp){
     currentHealth += hp;
     HUB_Health.text = currentHealth.ToString();
     Debug.Log("Healing");  //Show in console, but health does not increase in real game
   }
 }

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Cell
 {
   public Vector2Int gridPosition;
   public Vector2Int gridPositionNormalized;
   public Vector3 worldPosition;
   public string name;
   public bool occupied;
   public Character host;
 
   public Cell(){
     name = "";
     gridPosition = Vector2Int.zero;
     worldPosition = Vector3.zero;
     occupied = false;
     host = null;
   }
 
   public Cell(Vector2Int tPos, Vector3 wPos){
     name = "";
     gridPosition = tPos;
     worldPosition = wPos;
     occupied = false;
     host = null;
   }
 
   public void FreeCell(){
     UnityEngine.Object.Destroy(host.gameObject);
     occupied = false;
     host = null;
   }
 }