@pb4uski or @cathy63, my understanding is that a traditional IRA cannot be put into an irrevocable living trust. Is my understanding accurate?
The general problem that my friend is facing can be seen by assuming a $10M traditional IRA (not the case, but demonstrates the issue). I can't see any way to get it out of the estate other than withdrawals and gifting, or Roth conversions, and both of those result in ordinary income tax at a high marginal rate. For example, if my friend decides to wait until 12/31/2025 and make a $4M withdrawal to get the traditional IRA down to $6M, then my friend has $4M of taxable income, most of which would be taxed at ~40% or whatever the top marginal rate will be at that time.
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By the way, thanks to everyone who has replied. I've been collecting the responses and strategies and am starting to understand the landscape that my friend faces a lot better than I did when I posed the question.