Bitcoin isn't a single entity, it works by consensus.
When it comes to block; it means that all nodes in the network must have the exact copy of the block for it to be part of the Bitcoin blockchain.
You brother's wallet contains "coinbase transactions" (reward) from blocks that only his node knows since it's generated there,
but it's different from all of the other nodes' copy so it's not part of the Bitcoin blockchain.
In other words: it's "accepted" by his node in 2009 but not by the rest of the Bitcoin nodes.