To make some clearings.
He didn't lost 300k, as it was double payout in the database.
With an payout short after midnight of around 300k, which he received,after another 300k was dropped out, it is running smooth now.
To do some simple maths.

If he had all 600k, with a block reward of 500, he would have 1200 blocks on his own.
As far as I remember, the block height was around 4000 this time. So more as 25% should have been his blocks.
And this was just after the DB was resetted.