My mum has vascular dementia. My mum has auditory hallucinations, mostly happening at night.
I was told that the most important thing is how loved one reacts. Are they aware that the music isn’t really there? Are they afraid or can they come to terms with it ?
Happily my mum can distract herself although once when it was male voices she heard, she shook with fear literally. 😞
I would tell your relative it’s probably caused by bump on the head and as a symptom may pass.
Not 100 % true but ….