They don't have to pay layover for border crossing delays. But, every time I've had a undue delay due to the broker dragging their feet or something else that wasn't my fault, they have paid me layover. The one time they didn't want to pay me for my time, I told them the load needed to swap, right now, to another truck. I give the broker 2 hours from the time I fax the paperwork. If they can't get it cleared within that time, I expect to be compensated.
I'll give them 2 hours, after that the time delays starts counting towards the 2 hour wait for detention, and at 4 hours after I faxed the paperwork detention should kick in. If not, they have that 2 hour window to get me offloaded and let someone else deal with it.
I have never brought a load out of Canada that used DHL as the broker and not been delayed at least 5 hours. I no longer will even accept a load across the border if the broker is DHL, not unless I get it over the QC, up front, that any delays beyond 2 hours after faxing the paperwork starts detention immediately.
If he's been sitting at the border since 5:45 this morning, he needs to tell them to pay him detention, or get the load off his truck.