A small mistake on dice made my wallet get emptied. Only mistake is that I didn't added an additional zero to the bet amount. Instead of 0.00005 btc I mistakenly placed 0.0005 btc. Further on the consecutive bets went for a double the value. This all of the sudden emptied my wallet. I didn't watched the wallet until the bet amount in the tab turned zero. Further watched the bet history and understood what big mistake I've done.
Turns out that mistakes happen in a most unexpected way. You should have double checked your bets before placing it and continue to avoid mistakes like this. Anyway, still lucky you have only small amount on your wallet or else worse should have happened.
But that is not good if he only has a small balance on that site because he cannot continue playing gambling. As you said, he still lucky at least he doesn't use a big amount to gamble even that is a small mistake. By always checking the amount in every time of placing the bet will prevent us from placing a wrong bet, and we can prevent to make the same mistake in the future.
I think many gamblers have the same experience as him and we don't just make it one mistake but we already make it for more than 2 times or more. That is a good lesson for every gambler, and we need to take attention to placing the amount before we click the button, so we don't regret it later.