Well, only an extremely paranoid person, who has crossed into the mentally ill category would booby trap their house.
You know we had a house in a police jurisdiction that I used to work for that had a tear gas dispensing system. We just noted it in the dispatch computer, at the resident's request. None of the officers or the chief saw any reason to see him as "extremely paranoid" or "mentally ill." If they had, I'm sure they would have ordered a 48-hour mandatory mental evaluation at the local hospital.
So basically you're diagnosing him as mentally ill because he has undertaken certain activities inside his own private home that would only cause harm to intruders. Are you a doctor?
Do you carry a gun? Why? What are you afraid of? I think you're paranoid. (But I don't really think that, because I'm not qualified to make that judgement, and I don't think you are either.)