SueDonim- yes, sadly it does not work with everyone.
In the case of this lady, and perhaps musicians too - it does awake memories of sorts- but perhaps not for non musicians.
And perhaps just the 'wrong sort of music' for your friend. Maybe his family might know what he realla enjoyed, be it rock, or bagpipes, or accordion, or ....whatever. It needs to 'ring a bell' somewhere perhaps, to be effective. My OH for instance, would know what to play to touch me and have an effect.
My sil used to play the piano, not very well, not professionally, but she enjoyed it. She stopped when she developped Alzheimers, as she got very cross she was making mistakes. She had to move care homes a few times, for all sorts of reasons, and in the last one, there was a baby grand piano. Left alone one evening with my visiting brother, he asked her if she wanted to play? She could no longer string a sentence together - but he took her to the piano, and she played her favourite piece, without hesitation. She never played again and died soon later. Amazing.
For my mil, it was because she had not heard the nursery rhymes from South Africa for many many years- and never heard Afrikaans for many years too.