I hope you're not audited.
Donald Trump and the Republicans changed the laws starting in Tax Year 2018. Only businesses that hire employees and are not using their own 'special skills' (i.e. Football players, artists, hollywood stars) can take the QBI deduction. Referees fit into the 'special skills'.
My brother is works as an independent contractor behind the cameras for NFL, NHL, NBA games. He can't take the QBI deduction. It cost him a LOT of money this year.
I don't know where you're getting the requirement that a qualified business must have employees to qualify for the QBI, it quite clearly specifies that it applies to sole proprietorships. And the "special skills" you mention, actually called Specified Service Trades & Businesses, isn't an eligibility question but rather an income limitation. They still qualify for the QBI deduction, but it's phased out beginning at $315k of total taxable income for married filing jointly and completely gone by $415k. Needless to say, my income from officiating and other sources did not exceed $315k (or $157.5k for those not filing MFJ). Therefore, the SSTB limitation doesn't impact my QBI eligibility.
No idea about your brother's situation and none of my business, but if he's over the income limits and had his QBI limited, then congratulations on doing so well. If not, he may need to investigate better tax advice.