Waypoint Question(Conflicting Collision)

I found a waypoint script on this awnsers site that Im sure everyone is familiar with(and altered it a bit):

 var waypoints : GameObject[];
 var speed : float = 3;
 public var currentWaypoint : int;
 
 
 function Start()
 {
     waypoints = GameObject.FindGameObjectsWithTag("BossWaypoints");
 }
 
 function Update () 
 {
     if(currentWaypoint < waypoints.length)
     {
          var target : Vector3 = waypoints[currentWaypoint].transform.position;
          var moveDirection : Vector3 = target - transform.position;
          var velocity = rigidbody.velocity;
          
         if(Vector3.Distance(transform.position, waypoints[currentWaypoint].transform.position) < 50 )
         {
              currentWaypoint++;
         }
         else
         {
             velocity = moveDirection.normalized*speed;
         }
         rigidbody.velocity = velocity;
     }
     else
     {
         currentWaypoint = 0;
     }
     
 }

But my question lies with the rigidbody that is required for this script to work. When I have a rigidbody attached to the parent object(which also holds this script), the child objects' collision under it doesn't recieve damage or allow the OntriggerEnter to activate. How do I get the function for the child to work if the rigidbody is stopping it? This is the script that is on the child along with the collision:

 var hp : float;
 var replacementSpawn : GameObject[];
 var replacement : GameObject[];
 var scoreAmount : int = 0;
 var scoreHolder : GameObject;
 var turretReplacement : Transform;
 var turretMaterial : Material;
 var regularTexture : Texture2D;
 var changedTexture : Texture2D;
 
 function Start()
 {
     turretMaterial.mainTexture = regularTexture;
 }
 
 function OnCollisionEnter(collision : Collision)
 {
     turretMaterial.mainTexture = changedTexture;
     yield WaitForSeconds(0.1);
     turretMaterial.mainTexture = regularTexture;
 }
 
 //Take Damage Function
 //Subtract damage from hp
 
 function TakeDamage( damage : float )
 {
     hp = hp - damage;
     if(hp <= 0)
     {
 
         var i : float = 0;
         
         while( i < replacementSpawn.Length)
         {
             var y : float = 0;
             while( y < replacement.Length)
             {
                 replacementSpawn[i] = Instantiate(replacement[y], transform.position, transform.rotation);
                 replacementSpawn[i].transform.parent = turretReplacement;
                 y++;
             
             }
             i++;
         }
         scoreHolder = gameObject.Find("ScoreText");
         scoreHolder.SendMessage("ScorePoints", scoreAmount );
         SendMessage("Die", SendMessageOptions.DontRequireReceiver);
         Destroy(gameObject);
     }
 
 }