I would tell him that the financial direction I have and will continue to give him is more valuable than anything I could leave behind. If I left him $1,000,000 and he put it in the average mutual fund last year, it would be worth $650,000 now. If he left it in 'safe' savings accounts, inflation would outpace his interest rate and he would be guaranteed to have less buying power every year. But, if he paid attention to how I invested during this recession, he would be able to turn every economic downturn into a powerful investing opportunity instead of losing his inheritance. The money I'll leave behind will go to charities that teach financial literacy for those who don't get the learning opportunity he was given.
How much I actually leave to my kids might be equal to how much they have claimed to have donated to non-profits on their taxes over their lifetimes plus the amount of time they've spent helping the community.