I agree with your point entirely just don't agree with him only paying 5% (assuming no shenanigans). If he sells $300,000,000 only a small amount would get the 5% rate (see MONYman3's prior post).
I certainly agree with your post about the difference in payment by him and your wife. I pay 12% in short term gains here in MA (is that why you live in NH?) and feel ripped off.