@GMFan it sounds like he has developed the onset of dementia. My mother's husband (my step dad) has dementia and he hallucinates really bad. He claims to hear things and makes up stories. There are medications to slow it down, but not stop it. She finally got him into a home and it has been better.
There were a few times she felt threatened by him for sure.
Try to get them help if you can.
Just my $0.02