I wonder if these punters actually do any kind of research or go in blind before placing these high stakes bets.
I would speculate that he is probably watching Brazilian league every week and that he knew those games will be very defensive oriented with few opportunities to score goals. Still to play no goals at all requires big cojones

For instance I expected Wolves-Chelsea game to have max one goal in it after seeing Wolves playing awful in past few games and reading the line up of Chelsea without many first team attackers. I think I even put a prediction in Premier League thread or somewhere. Still I went for much safer under 2.5 goals on my ticket and not "no goals" option. The difference in odds and risk is not comparable. That guy has a lot of money or no risk management.
There are two problems with your statement. As far as I know this is not just one person, Brazilians as a group end up gambling here on big parlays and end up winning, no idea if it is just a few people or a whole big group but I remember steve saying it wasn't all the same Brazilian and there were a few different ones that gambled this way, this is why I assumed it was a cultural thing.
Secondly, I watch ever ysingle premier league game every single week and if I ever do a parlay, including every single game of that week, I am pretty sure I will get just 50% correctly, some weeks more and some weeks less but not 100% correct. Just because you are watching a league doesn't make you suddenly a master about gambling, it doesn't work like that.