I think you need to add something to the enemy code.
However this is based up on the weapon code you use.
If your weapons use the "ACTIVATE_SHOOT" flag you simply need an event function for the enemy which reduces his health points when his event is event_shoot:
Code:

---

function enemy_events()
{
  if(event_type == event_shoot)
  {
    my.healthpoints -= 10;
  }
}

action enemy_fight
{
        var move_dist[3];
	var distance;
	
        my.enable_shoot = on;
        my.event = enemy_events;

	my.healthpoints = 100;
        //rest of the code

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