Am I allowed to help him via PM?
No. Only those that have proven themselves are allowed to help. Regardless of whether or not you agree with our rules, they are put into place to make sure that our members get help from members that actually know what they are doing. We do not know you. Secondly, we monitor PMs as necessary to make sure that our members are protected, again, to make sure that they are getting help from people that really know what they are doing. If you make a mistake, we won't be able to catch it. That is why all help is done in the open.
If you really know what you are doing, enroll in the HJT classroom and prove it. If you try to help someone via PM and we catch it, you will be banned from the site.