My MIL dated a very rich guy who wanted a 100% inheritance tax. He said that his kids should make their own way. He also said that a 100% tax would prevent vast fortunes from coalescing to individual families like the Rockefellers, etc.
That last one is not unreasonable.
If he doesn’t want to give it to his kids he can donate it all. Giving it to the govt creates the same kind of problem he is trying to avoid by letting politicians and such use it to enrich themselves.
Did you tell him there’s no law against him giving all his $$ to the government and not worry about other people’s $$? I’m amazed at how many idiots are out there who think government spending is a noble activity.