Not ideologically pure.
I’m super happy with my Fairphone 3 as well (I upgraded the camera to 3+), but the newer models seem to have made major improvements indeed.
Still, for anyone who doesn’t need anything too fancy but who insist on having a headphone jack, a used Fairphone 3 is a good option. Buy a new battery for it and it’ll be good as new. :)
One option might be to use Mycroft, the FOSS speech assistant. If I understand correctly you’d have to install support for playing local music - I found one such plugin, but it hasn’t been updated in a few years so who knows if it’ll work.
At least he seems to be enjoying it, embracing the creative process and developing whatever he’s interested in. Seems like a pretty healthy approach.