The reason? ( And FR CPA, Real Estate Investors, etc please chime in ) It is because with his kids running the biz if he get POTUS they will essentially have their margins exposed and how they run their real estate empire and how their competitors with knowledge of said margins can undercut them.
Never got that far in Accounting, my guess this is 300 level and higher stuff, i.e. purchase cost, amortization, etc etc revolving around high end properties either as rentals or for sale, not to mention the golfing end of the business and a bazillion other interest he has...
I was a CPA early in my career and completely agree.