Nice works: I'm not sure what kind of answer you expect, if you really except a serious answer, and are not just trolling.

Yes, it is of course possible to win an unlimited amount of brains in three wins - you enter a tournament with four participants, where X brains are offered for the winner, and win your three games. You will get X brains; with no upper limit on X. Is this the answer you wanted?

Realistically, the player has not won his brains that way; he either got them through cheating, or bought them, or as a donation - I got a 1000 brain donation some years ago, when I asked nicely for tips to be able to join those tournaments.

That approach might work for you too, but I'd recommend to reconsider the wording of your posts - if people see them as trolling, they are more reluctant to donate you brains. Otherwise, of course, you can write what you want.