Custom field to enable or disable comments

allow_comments.php

<?php  // <-- you probably dont need this line

add_action('geodir_after_save_listing','_my_update_comment_settings_on_save',10,2);

function _my_update_comment_settings_on_save($last_post_id, $request_info){
  global $wpdb;
  if(isset($request_info['geodir_allow_comments']) && $request_info['geodir_allow_comments']=='1'){
	    $wpdb->query($wpdb->prepare("UPDATE $wpdb->posts SET comment_status = 'open' WHERE ID = %d", $last_post_id));
  }elseif(isset($request_info['geodir_allow_comments']) && $request_info['geodir_allow_comments']=='0'){
	    $wpdb->query($wpdb->prepare("UPDATE $wpdb->posts SET comment_status = 'closed' WHERE ID = %d", $last_post_id));
  }
}

does geodir_after_save_listing still work?

@leem2209 no, that was for GDv1, in GDv2 it is "geodir_post_saved" and a little different. I don't think we send that godire_allow_comments now so you would need a different trigger https://github.com/AyeCode/geodirectory/blob/master/includes/class-geodir-post-data.php#L702