Make sense, never get greedy. Play gambling games with clear mind. The user obviously got too much greedy about winnings.
It is actually possible to win such big amounts from a small amount like 18 bucks, but the request to deposit money was a clear red flag and he should have immediately stepped away. No site asks for such deposits. They only focus on wagering requirements.
That's what you get for gambling on non-reputable websites. Stick to vouched reputable websites and u wouldn't have this problem.
You aren't really helping his case by pointing out the obvious. Instead of criticizing him negatively, learn to offer positive criticism. Op clearly lost a big amount and criticizing him in this manner makes it worse for him.