IDK, I'm not so sure about this. Having heard only a limited set of facts, a few important points jumped out to me:
he works for a hospital "in the office"
he was asked to affirm his Status AND his VL and CD4 counts
this was not the only question on the form, there were others not about HIV status presumably
I think this is more routine than it appears at first glance. If i had to guess, this is about the hospital shielding itself from legal liability more than anything else. I would almost certainly bet that Ottawa law has an exception for health employers. These are settings where the accidental transmission of bodily fluids is highly regulated and managed. So much so that hospitals keep a playbook for what to do when it happens and log every single occurrence.
Now I couldn't care less if the person administering my healthcare is poz or neg. But if they are poz, then there is a REAL risk of that person infecting a neg patient if they aren't managing their health and remaining undetectable.
The form isn't targeting you for being POZ, it's making sure that if you are poz you are also undetectable so that you aren't putting patients in undue risk.
The last thing I would say is that while you may think your wife is the only one who knows your status, there are likely many MANY parties in your Health provider chain and the Government, thanks to your single payer health system, who do know your status. You shouldn't be surprised that they all talk to each other as well. While I deeply believe in your right to reveal your status when and to whom on your terms, if you've been fired over this already I'm SURE your employer and your union can deduce what your hesitation to fill it out was tied to. The ship has largely sailed on your original privacy concerns if what you say about your employer and union are true.
I wouldn't feel good about signing it either, but I also can appreciate that a hospital NEEDS to ask these questions to protect patients and staff. That's what this is really about.