

Hormone imbalances can’t overcome thermodynamics. In people with hypothyroidism, the set point of their resting metabolic rate is lower, leading to fatigue and often being too cold.
So it’s not that they gain weight despite a deficit, it’s that a deficit for them would be less calories than someone with more activity who isnt cold all the time.
In a perfect world, calorie needs match with hunger, so with decreased calorie needs, you would naturally eat less, but it’s not always perfect so some people with hypothyroidism have “normal” hunger when they actually need less food. It ends up with 1/4-1/2 of people with hypothyroidism experiencing weight gain.




Assuming you mean in the US, there is a national system called NICS that basically has the FBI run a background check. Some states have additional systems to augment that.
The conditions that get you put into the “no” list are things like committing a felony, domestic violence, drug use, etc. Being committed (against their will) to a mental institution is on that list. A mental institution would have to report you with evidence to get you added to the list. Potentially, he could ask his psychiatrist to do that for him. It may not be an option, but if you brother is worried himself, that is good evidence, I think.
When you buy a gun, you have to check boxes on a form to say you aren’t a felon, addicted to drugs, a fugitive, etc. They can check the felon and fugitive part, so if you lie, you get in big trouble. Drugs, though, they obviously dont have a list, so really it’s just a way to add penalties if they can later prove that you lied (e.g., hunter biden). You couldn’t just do a drug and automatically pop onto a list.