Invisible Aliens in home

My mother in law has been saying for over a year, that her home has invisible aliens attacking her. She can only see where they are when they turn on their red lights. They make horrible sounds in her ear. One in particular follows her everywhere she goes. They bite her all over her body. She has had black bruises on her hands. I have to wonder if this is just bruising because she is 91 years old. When she eats, she has to take a quick bite and then cover her mouth so "he" cannot get in her mouth. She claims one night she put on a huge coat and got in bed. When she woke up the coat was on her backwards and she had to struggle to get out of it. She says she can catch them sometimes and squashes them to death. They also leave a horrible odor. She is adamant that this is happening to her because she saw a UFO near her home about 45 years ago. All of this started after my father in law passed way. I am wondering if anyone else has had this happened to them or heard of such.