Wasn't on an airgapped device?
Not multisig?
He reported a server of his having been compromised less than two months ago:
PSA: My server was accessed this morning by an unknown person. Full analysis in progress, but take extra care that you PGP-verified any downloads. #Bitcoin
Security practices that might have been adequate in 2013 (by necessity with essentially no alternative) incur significant risk if still employed a decade later. Sorry to learn this occurred, but it most definitely did not have to.