Your boyfriend shouldn't be in danger of not getting a WP. If the employer wishes to keep him, and he continues to meet the requirements of his nomination, everything should be fine. The main hurdle that the new regulations would be throwing at him, is that his employer would need to submit the required paperwork and fee before he's able to apply for a new WP (the one that he can get with the nomination certificate and support letter). I know a few companies here in metro Vancouver that would not agree to pay the fee, but if your boyfriend is a trusted worker and is contributing to the company (which he obviously is since he's already being supported for the nomination), then it shouldn't be too much of a problem.
If his current WP expires before he gets the new one due to the delays that the new regulations are causing (which I think is what you're worried about), he should still be fine. His nomination process won't be jeopardized as far as I know, he's just not able to work for the short time that it takes to get the Employment Standards number and apply for the WP. And obviously he needs to make sure that he has some kind of legal status in Canada during that time, visitor being the obvious choice. It would become a problem, though, if the employer said that they're unable to continue to support his nomination due to the delay, i.e. that his job will be terminated if he's unable to work for a week or two.
When I was waiting for my BCPNP processing to go through, my WP expired and I had to stay in Canada as a visitor for 2.5 months without working. But this is perfectly OK on nomination level. The nomination won't be invalidated or anything even if the nominee has a short gap in his employment history, as long as the company is still committed to keeping them employed once the new WP comes through. My employer was thankfully OK with waiting for me until the nomination came through. In your case, getting the required documents shouldn't take an enormous amount of time, and since I understand that you guys are able to drive down to the border eventually to get the WP issued, you're already saving a lot of time there.
So let me know if I completely misunderstood something here and I can try to help more.

But to me it seems like you guys shouldn't be in trouble because of this. Also, since the CIC bulletin was released in a very hasty schedule, I'm fully assuming that they're going to come out with some more practical information regarding this soon.