Some symptoms are likely to be affected by fatigue, especially cognitive symptoms, like memory and confusion, so are likely to be worse in the evenings. But your mother sounds very confused, perhaps more than would normally be caused by fatigue. Has she been drinking a lot? And do you know what drugs she’s taking, and the dosage? Perhaps it would be a good thing to check her medication and the dosage of different pills. Make sure she’s not taking more than she should be of anything. You could also see if there are any that shouldn’t be mixed together and/or with alcohol? Perhaps ask a pharmacist?
If you rule out drug and alcohol problems as a cause of her confusion, then it sounds as though she needs some help. Do you live with your mother? Or does she live with anyone else? Is she normally more clear headed? If so, then perhaps you could gently raise the subject with her. It’s possible she has noticed herself and is worried about her cognitive function.
Ultimately if it’s the mix of drugs causing the problem, then you/she needs to get that addressed by her GP. If there’s an alcohol problem, then you’ll need to tread carefully as no one likes being told their drinking is a problem. But if it’s neither of those, really the GP or neurologist would need to refer her to a neuro-psychologist.
This whole area is one that calls for a very light and sensitive touch. If your mother isn’t aware that there’s a problem, then it could be very upsetting, so treat her gently.
Best of luck.