As wallets have become more secure would these coins not be moved to something considered "safer" ?
He probably just saved his private keys in an encrypted container. They were never really in a wallet other than bitcoind.
When was a large chunk last moved? If it was years ago does this not support the likelihood of a lost key and the inability to access these coins?
These coins weren't really moved at all. They're just sitting in the addresses to which they were mined.