The good old method is still physical destruction by breaking the disc into pieces (use protective equipment), then douse it with some flammable liquid and set it on fire, and scatter the remains in a landfill.
But is something like that really needed if all he has is Ledger Live app? I mean I could understand physically detroying drive if you had Electrum or similar type of wallet, but in his case where private keys never left Ledger what kind of info could someone retreive that could endager his crypto, even if they manage to restore the data?