The Millionaire Next Door by Danko-Stanley. In a subsequent book Stanley writes that a decamillionaire asked him to judge a cash-prize book report between his grandchildren on the book. He wanted them to read and absorb that one book so much h was going to pay $500 as an enticement. (Don't recommend that amount, just th book.)
You can also get audiobook versions of that and similar and just play when he is in car w you or while making dinner.
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