That is what I was thinking as well, this is the kind of win that would be huge for those that are not really used to making such a high bet, but most likely this gambler is used to bet that kind of money and if anything the amount won could not be a big deal for them.
Still the odds of winning that bet were very low so without a doubt the gambler must have some skill when it comes to sport betting, as I find difficult to believe someone can win such a parlay by luck alone.
It is maybe a combination of knowledge and luck but mainly luck in my eyes lol; with these kind of multibets something always can go wrong. He probably knows something about NBA and placed handicap bets on the favorites of all games. But as you mention, this is a very nice amount but probably not life changing for gamblers like this.