You seem to not understand how economics work, the issue with higher taxes has never been that people don't keep enough of their money, the issue is that people tend to hide their money using loopholes such as offshore bank accounts (which reduces tax revenue), and also that it leads to stagnation in the economy (which reduces economic growth). Second, to the extent that the current tax rates are "high," this is entirely the fault of regional governments not the national government, so if anything if you want lower taxes, there should be more centralization not less. I do find it odd how the right wing has decided to try to sing both tunes on this issue by wanting lower taxes yet continuing to support greater powers to the regional governments, which have written their own totally absurd tax codes. A 50% marginal income tax at the federal level is not particularly unreasonable, but stacked with a 30-40% marginal income tax at the regional and state-level, it may indeed be. However, this is entirely the fault of the regions and the states, so I would suggest that your outrage may indeed be misguided and misdirected. If you want lower taxes, moving towards unitary government would be the best course of action (other than the fact that it gives power to gasp the evil scawy bureaucrats)
Do not give him terrible ideas.