If he did, then it was because those addresses were generated insecurely (e.g. brain wallets), or he had some additional information or knowledge about those addresses. No one has ever or will ever randomly stumble across the same private key as anyone else, period.

Given that most lotteries have a chance to win the jackpot in the region of 1 in 10⁸, and there are around 10⁷⁷ possible private keys, then you are a few trillion trillion trillion times more likely to win the jackpot 5 times in a row than to find a single previously used private key.