He didn't lose focus, he lost money... $3M is a lot of money, but not for him, I think he can afford to lose this amount. I like what he said about gambling and life, he is pretty much an honest guy with some crazy life experience, so I think he can be trusted. Life is full of ups and downs, and sometimes crazy shit happens to us, but instead of crying for losses, we need to suck it up and continue fighting. I agree with him that people who fight with depression should stay away from gambling (and social networks), and people who have a hard time when it comes to dealing with downturns should stay away from gambling.
While I'm of the opinion that gambling is not for the faint of heart, I'm really surprised how you would easily proclaim him to be trusted and honest? Unless you know the guy personally, you might want to take whatever he said especially experiences with a grain of salt. Gambling is a risky business and only those that have the stomach to take on negative outcomes, should indulge. In my experience, losing a bet is hurtful for everyone but some people have come to the realization that you're never going to win all. You will win some and lose some.
At the end of the day, staying pessimistic makes it easier to deal with gambling outcomes. This way, you're not surprised or disappointed by the outcome if it doesn't go your way.