We're not talking about the same situations or conditions. Brakes are only required on both axles if over 6100 lbs
also towing a trailer behind a large DPMH has different requirements brake wise over say pulling the same trailer behind a small pick up.
Brakes are not required on a toad weighing less than 4400lbs and is less than 40% of the gross vehicle weight rating of the MH
The other thing is you can't just say Canada. We have ten provinces and every one has different laws. The ones I am familiar with are BC.
So in some provinces your friend is correct and in others not so. I should have clarified I was talking BC.
Also note he was not stopped at the border. Border patrol are not MOT and have no jurisdiction regarding brakes on trailer axles etc
I been through the border hundreds of times over the years and have never once heard of or seen any border guard do a mechanical inspection or inquire.