Its hard but at the end of the day shes a grown adult apart from being your mum so theres only so much you can do. Mine had dementia for a few years before she passed and the only way I could make the visits bearable was to get her out of the home and take her for a drive, she liked listening to music in the car and seeing the countryside. DIfferent for you but you need to find something that she likes to do so you can keep in touch with her. Tough though.