Only a risk-taker could do that, someone who can afford it even if they lose, or at least has the courage to try betting that amount. And it seems the bettor really knows the game of basketball; he probably thought this through. If it were me, I probably wouldn't do it, knowing that there's no guarantee of winning. I can't imagine myself getting lucky, especially in sports betting. I would likely hesitate and regret it if I ended up losing. But it's also really nice to try something new from time to time.
Yes, only a risk taker can do that and those people who has a lot of money because they didn't even care if they will win or not. What"s important to them is to place a bet and let them see what happens. As you've said, gambling is about luck with a little bit of strategy and familiarization that's why there's a small possibility of winning but there's no 100% guarantee.
Before the publicity of Op's friend's winnings, he must have been through a series of losses. Then shows up his win after a big win. It's common for gamblers to share their big wins. However, gamblers take risks in games they're able to analyze. Can't predict correctly any basketball games, but would watch and enjoy the games. A lesser guarantee of winning is what brought him the wins despite numerous cases of losing money, which may not have been unveiled. Hence, it's to anybody's detriment to gamble because of the result of this gambler, they may not be able to go through the challenges of gambling in the early stage. Gambling and not minding the result is a good quality for responsible gamblers but with some criteria that may interest any gambler to practice; self-control, splitting bankrolls, and time limits. A gambler who focuses on having fun can easily wager money without minding his results, while a risk taker who doesn't follow the criteria listed above can experience a gambling problem.
Those criteria can serve as a gambling strategy and also require a bit of luck on the player's side. When in lose it's still okay to hold on before continuing to gamble again. It'll only help in stabilizing our gambling urge and also keep regrets at a minimal level. Regretting after losing in gambling is not wrong, but continuously doing it is quite not recommended for any gambler. Getting to a point where the gambler doesn't regret anymore could be possible and that's a well-known symptom of addiction. Since the gambler is required a long time of play, most the times, to gain a big win like Op's friend. If he doesn't control his emotions, he may not be able to get to that point, of winning big. When the player is prepared to try new things, especially, he's required to follow due routines and understand at first the new game, then keep to a low pace of consistent gambling in the game.