Overriding Plugin Function in Child Theme

In general you can not override functions or methods in PHP. Code can be written to support such things, but it needs to be planned in advance, and your snippet is not big enough to be able to decide if it is possible or not in your case.

The good thing, is that you do not need to override any function at all as the output of that function is filterable by using the 'property_meta_boxes' filter, so just do something like

add_filter('property_meta_boxes','wpse223273_meta_boxes');

function wpse223273_meta_boxes($metaboxes) {
  $my_meta = array(.... your meta box settings....);
  return $my_meta;
}