If you have these serious doubts, and feel that the school or its principal cannot be trusted, then walk away. You place great significance on the lack of "JAA" accreditation, and clearly the school doesn't have it.
It is almost certain that however and wherever you do a course, it is going to involve you in significant cost at some point. Despite this, there are no guarantees and you should prepare yourself for the realities of this likelyhood.
If you can't, then don't do it. It sounds like it may be a good opportunity, but it certainly won't guarantee a seamless progression to airline flying.
Nobody here is going to able to convince you otherwise, so the choice of what you do is simply yours.
That is a responsible opinion.