I made the mistake of letting my neighbors know I was planning on getting bees. All my neighbors were fine with it but my neighbor right next door. He went berserk and even went as far to threaten to kill me if his wife got stung. That was 6 years ago and we are still not talking.
My dad had 5 hives on his roof for 5 years when a neighbor asked him if he was still thinking about getting bees.
I go with not telling them.
Wholly shnikeys, kill you? Was this the first time he gave you hunts of being unstable? Do you have bees at your home? I'd almost have to get bees at my home at that point (I do have them there) just to show I'll not be intimidated by threats.
What if she gets stung by a wasp, bumblebee, or something else? Is he the type of guy to act upon threats or is he a chest thumper? I'd still give that guy a jar of honey (to try to keep the peace and try to open sane conversation) every year but a definite wide birth. A jar of honey is a great ice breaker.
Years ago I had a older neighbor who I got along with go after my wife verbally because she was the neighborhood association bookkeeper. Dues had been raised from $40 to $50 as maintenance costs had gone up as volunteers had gone down, notices were sent out by the secretary, and she was merely where you sent them. We had words when he called back to give her more of his mind. After that I was cordial but nothing more. About a year later he apologized and our relationship resumed, but I was a still guarded.