Thank you for the additional information.
There is something about your mother that your cat does not like. It may be difficult to figure out exactly what is causing her so much stress and tension, but it may be something as simple as the perfume or body wash that your mother uses. Cats are very sensory animals, and more than likely there is a smell associated with your mom that she doesn't like.
I've found also, that if you can't figure out exactly what is causing the problem yourself, sometimes having a feline behaviorist come in when your mom is there can solve the problem very quickly. Your vet should be able to give you a referral and they are usually not very expensive. I would first try to figure things out yourself - again, it's probably related to smell - and not necessarily a smell that you find offensive - it may be something that smells wonderful to you.. I would start there, and go to the behaviorist if you find it necessary.
Feline Healthcare
16 yrs health care mgmt & issues relating to cats, reproductive issues and multicat environments