Then I guess he also needs to know if you have knives, a roof you can jump off of, a car you can drive over a cliff with etc.
If a person is going to commit suicide, do you think they might also be compelled to lie about their gun ownership?
Likewise, preventive medicine would make it important to know if youre caring for a pediatric patient whether or not parents store their firearms in a way that kids cant access them.
What? And if the answers to those questions are not satisfactory, what course of action do you suggest the doctor take? Should he be held liable if he does not take any action? Is he compelled to report you to the authorities so they can then confiscate your weapons?