Alfred Brendell, flying on all cylinders: Piano sonata #54; Here's what BBC offerings look like {sob--we gets Mairzy Dotes here, quite more often).
I left-in the post- [?] addendum; unclear if BBC copies U-Tube, which needs those..

Dunno if this fits within your Son's skill set.. but Master Brendell raised goose-bumps here (his history amazes as well). To moi, passages sound like Mozart-would-have grokked to fullness; hey! it's a Two-fer..

Cheers,
moi

Maybe look-up a Gigundo-virtuoso pianist of yesteryear, Simon Barere

(My HS teacher/friend had a LP of the/his Liszt', 'Variations on a Theme from Don Giovanni'--familiar tune to all).
Fey factoid: he went out Exactly-the-right Way, while playing. (The opus--Muy had the score!--showed moi the first scripted
"1/128th note". And yes, we do remember the weirdest-little-Things).

aka: One's Aim (should be) ---> a bit farther than one's Reach.
(Though por moi ..trumpeter/flugel-horn guy Sergei Nakariakov's abilities) exceed even those earliest What-If?-imaginations
about, (what I 'Wish' I could 'sound like) ..by greatly exceeding that fledgling imagination. :-)