I didn't downvote, but it's probably because of the lack of understanding and/or fear-mongering around privacy/anonymity.

Yes, he'll have to report the donation and pay his taxes. Yes, someone may "take a close look". No, there is no chance he'll be legally prevented from accepting the donation, unless he lives in an authoritarian country like China/North Korea where owning crypto at all is illegal.

Crypto has been used for anonymous donations as long as it's existed and afaik nobody has ever faced any legal problems from accepting an anonymous donation. https://en.wikipedia.org/wiki/Pineapple_Fund