I was thinking on this while i ran to town....
If he has only been Dom for 3 years .. he should not have a problem with you discussing that there is a problem with pushing to far continuously.
How do you train to be a Good Dom? very good question. I think either one has it or they don't. IMO. If some one has to be made to consider options and the compassion of others... it's going to be a long learning process.. some take a lifetime and never get there.