For income over $721k, California's tax rate is 12.3%, which is high, but I still don't think this makes much sense.
The average annual inflation rate since 2000 is 2.7%, so $900k in 2035 will be worth about 70% as much as it is today. His last payment will be about 30%. He'll end up with about 50% less due to inflation to save 13% in taxes up front.
And that's assuming there aren't any major political or economic changes over the next 10 years that drives inflation significantly higher than that average.