They purr. I love the sound of bass. It relaxes me, particularly around my diaphragm which seems to be where I carry a lot of tensions. This is also one of the reasons I love the Foo Fighters and bass heavy metal music, or pretty much any bass heavy music.
The bass resonates throughout my abdomen and calms me down. Now, I know it seems like a contradiction in terms to be relaxed by heavy metal and it’s true that much heavy metal just winds me up and annoys me (treble-heavy music like AC~DC or Iron Maiden or Guns and Roses), plus I’m not really interested in screaming about death ‘n’ stuff.
Nevertheless, cats and bass relax my diaphragm and put me in a good mood. I’m not saying that I want to listen to pounding music at 7am in the morning, no, but if your Aspie child seems to like this music or likes lying on the cat and the cat doesn’t seem to mind, it’s for a good reason.
The purring helps.