That's a big amount of money if you will try to use it in trading, but if you will just invest it in a casino I believe you need to wait for a longer time before you will be able to meet your goal. Investing in gambling sites are profitable but not lucrative when you do not have decent money to put it.
Think of that, you better increase that amount in trading then invest in casinos afterwards.
Even though it will took long time to reach his goal, but it's quite safer than he using it for trading. The only risk while you invested your money in gambling site is you will lose your investment if the site closed before you withdraw your money (rarely if you have invested in reputable sites) and your investment amount decreased because of whale's winnings. We know if trading has higher risk than investing, he also said if he doesn't have any spare time to do trading.