IANAL but I imagine that the donations are in brave tokens and it may or may not be treated as cash (even though the eventual payout is cash) which may or may not be legal depending on a lot of stuff that's beyond my area of expertise.

But if the idea was to 1) create token and 2) YOLO and yeah, lawsuits incoming.

But it could be that they have good lawyers and that it is actually legal (although as I write it I don't believe that, haha)