Braunbehrens once bubbled...
There is no "DIR based". You either teach DIR and know what you are doing, or you are misleading people. Solo diving in a wet suit is not DIR, and saying "I prefer not to dive DIR" is a tip off that you can't teach DIR.
What do you want him to do solo dive in the nude?
DIR is not just about wearing the proper equipment.
For most it is
I would warn anybody away from "Dive sherpa". He sounds very dishonest, and it seems to me he just wants to make more money by "also teaching DIR".
Dishonest implies that you cought him telling a non-truth. Where? I think you are dishonest or just got off a boat or something.
Before you send someone into a cave you ought to accept some responsability for what you do and what you don't know, and not mislead them.
Maybe you would like to list your credentials so I can compare them to my future instructor Mr. Divesherpa's. For all you may know you may be warning me away from a very good instructor. Shouldn't you be honest about what you know and don't know?
And please, "all in good fun" WTF is that supposed to mean? You teach cave "all in good fun?" Cave diving is far too dangerous and serious to be taken so lightly. Yes, you can have fun doing it, but you don't mislead people and then say it was in "good fun".
I'll go slow. Try to follow F....U....N means having a good time, telling a joke, doing something you enjoy. Not only is cave diving fun but sometimes it can be funny. Work is serious. You are serious but cave diving and chat sites are for/in fun. Did that explain WTF it means?