FWIW

All distributions from your IRA is taxed as ordinary income based on your tax bracket.

All the capital gains in your Ira Long or Short does not mean anything I mean no immediate tax implication.

based on your scenario if he takes $250k or $10 Mill he will pay the tax as if every dollar is ordinary income .

max. tax rate 35% federal and 9.3% Ca .

JMHo