I'm not sure about your advices. Since he's in the lower league, I don't think he should be bothering about convenience of his playing positions. If he's willing to pay a level 6 trainer, he obviously cares about the trainee more than the club results.
My guess is that he has a level 6 trainer because like many newbies, he figures incorrectly that's twice as good as a level 3 trainer. My advice to him would be that you can still put a premium on training with a cost-effective level 4 trainer and that way he won't be murdering his economy in the process.
There's no sense in training a player to a high level if he can't get out of DV because as we both know, eventually he won't be able to afford that players high salary along with a L6 trainer and all his other expenses. That's just reality.