FWIW, no i dont condone this practice. It has disaster and tragedy written all over it. You would have to ask yourself this question..."If my ________(enter here son, daughter, wife, friend) dies due to my incompetence, could i live with it? If you answer yes, you need to be commited to a mental institution.
However, I was not taught how to dive by a certified dive instructor. My grandfather taught me how to dive at a much younger age than what is currently allowed by all agencies standards. He was a fantastic teacher, and taught me more than any course than I have ever taken. So can a "Non-Instructor" teach someone to dive? Yes. Would my grandfather have ever done what we are talking about here? Hell no.