No problem, but you may also need to add that post.php skip/bypass rule too. 50/50 chance of that so once you make him an Admin then have him test things. If the problem is still occurring then add the skip/bypass rule.
He would need to be an Administrator for that “fix” whitelist rule to work. So the process would be make him an Admin, have him check things, if things do not work after he is an Admin then add the skip/bypass rule.