I agree with you. I think I will inform NAPIT because the company has someone reg NAPIT but that person neither inspect nor signs the form. Once I'm gone I will inform...Unfortunately sounds like a boss who's 'advice' would not be worth learning from anyway in terms of doing a competent or good job.
You'll have to decide how you feel about what you're doing - if you are only doing a visual inspection then you can at least still do that properly and to the best of your abilities (checking bonding is in place and the right size, looking for damaged sockets, light fittings etc). while getting some experience of the reality of houses.
What your boss does you cannot do much about unfortunately, other than decide whether you want to keep working for him.
I don't suppose you know whether he is registered with the NICEIC or NAPIT? If so you could consider informing them of what he's doing (though probably only after you've decided you can no longer work with him naturally...)
Thanks everyone for shedding some light on the matter.