Even though my Mother wears an alarm necklace and has pull cords in her assisted living apartment, she is scared of being alone at night. How can I help her?

My Mother goes through bouts of this as well. I cannot tell you why it happens because she has never been a "fraidy cat." She even got to the point of begging me to hire someone to sleep at her apt. every night. It took me weeks of convincing her that she would basically be paying someone large sums of money to watch her sleep. Also, if the caregiver was asleep too, of what help would she be? This all fell on deaf ears because it was an irrational fear.
I am not sure what causes it, perhaps fear of dying alone, or being in distress and not having anyone right there to help. Whatever the reason, it was real to my Mom.
I tried the alert buttons and even gave her a cell phone, but she would never carry them around with her - which renedered them useless.
My Mom is not in an ALF - I thought that would remove any fears of being alone at night.
I think it may be lonliness...those wee hours of late night and early morning are hard for seniors. Also, we do not sleep as well as we age and sleep deprivation can cause some irrational thoughts.
I finally got Mom to drink warm milk at night. Her doc said she could have little red wine. Or I have her take an excedrin just to calm her nerves.
If I had gone over to stay with her every time she called, or hired someone, I do not think that she would ever have been able to stay on her own again.
good luck