That would be breaking and entering, and theft, and I also can't be certain he even has a copy at his house, I also need to get it witnessed and notorised for my application, which is harder to do stealthily with my disabilities.
I do not want to break the law in order to get a passport of the country I'm a citizen of.
My mother and he are long divorced.
This is very true, though I don't really care how the family gets destroyed, I don't want to have a destroyed family at this point in my life right now because I need their support in other ways, so if I can avoid pulling the pin on a series of events I know my father will choose to react poorly to, I want to save myself that stress.
I know my mental health could not handle a family break down right now.